They would if they were going to rebid NT. Say you were playing a 15-17 NT and had 13 HCP and were 4333. You open 1S, pass partner’s 1NT or 2S and over any other 2 bid rebid 2N.
Do you really mean that 1S - 3H is a “raise”, i.e. guarantees spade support, or just that it is a game forcing bid? I have played ACOL, Standard American and 2/1 and have never come across 3H being a raise in any of those systems, but in all it would be a game-forcing jump shift showing hearts.
I agree with the rest of the post and comments by others about Jacoby 2NT and splinters (limited in high cards) being the way forward with game-going hands, leaving a direct 4S for weak, distributional hands, e.g. Qxxxx x Axxx xxx.
For splinters, I like a style where there are two levels of splinter - 9-11 HCP and 12 - 14. You show the former by bidding one over the trump suit, i.e. 1S - 3NT and 1H - 3S. These say “I have a game force, 9-11 HCP and a singleton/void somewhere.” If opener has no interest in slam, he signs off in 4 of the major and you have not given away the information to opponents about where the shortage is. An immediate splinter shows 12 - 14 HCP.
Traditional Jacoby 2NT has some flaws, principally that the sequence 1S - 2NT - 4S (showing a minimum) preempts responder if he has a very good hand, so now has to make slam tries at the 5-level. Experts generally use modified responses to J2NT.
On the actual hand, no matter what you play, 4S is way too wimpy with that mountain.
You are correct, I was misunderstanding. It’s an unconditional game force, but says nothing about Spades.
I’ll still defend it as the best way to handle this hand if you’re not playing something like Jacoby - you need to get your strength across and 4S just doesn’t do that.
It gets more awkward if you don’t have a second suit to force in - Murphy says that that if you force with say 1S - 3C on a 6-3-1-3 distribution, partner will immediately raise your phony suit, though in practice you can usually investigate slam and then correct to Spades.
I dislike the 3H raise as it consumes too much bidding space. 2H or 2S over 1 of a minor would be a different matter. In this case the bidding would go 1S - 3H - 4H and you’ve missed the opportunity for cue-bidding and have to go straight to Blackwood.
Questions about Jacoby 2NT playing 5-card majors.
(1) Does anyone play that that bid is allowed with 3-card support? It seems to me that over 1H, any other bid with, e.g. Ax-AQx-Kxxx-xxxx, just muddies the waters unnecessarily.
(2) In response to 2NT, opener is supposed to bid 4M, 3NT, 3M with a minimum, above-minimum, or strong hand respectively. My regular partner insists that this is unnecessary precision as to strength and that 3NT should show a 5-3-3-2 suitable for play in No Trump. Do y’all agree with me that he’s wrong? 
(3) Some advocate that in response to 2NT, opener needs a sound opener (13 hcp OR a good suit) to show his shortness; with 12hcp or less AND a mediocre suit he should bid 4M despite the singleton. This makes sense to me. What do others think? (Replace the 13/12 hcp with 12/11 hcp if you open super-light.)
Kibbitz mode ON! 
I have seen it, but rarely. I do not. With the hand given, you bid 2D then 4H next time. There’s no need to bid 4-card suits up the line when you intend to support hearts next, so you should show your better suit.
I agree with you. You have used up lots of room with the 2NT bid so to bid 3NT without giving any indication of strength means you get to the 4-level before being able to explore. And how often do you want to play in 3NT when you hold a 5-4 major suit fit?
I posted elsewhere that I think the jump to 4M is a weakness of traditional J2NT responses. I prefer a bid of 3C to show a minimum. Responder then has a means of asking for shortness (3D). However, if not playing that method, I prefer to show shortage if I have it to avoid preempting partner with a 4M bid.
Here is an article on J2NT and alternative responses. https://bridgewinners.com/article/view/limited-bidding-reengineering-jacoby-2nt/
Dammit, I missed out on 7N last night. I’d gone Blackwood and squeaked when my partner was about to pass my bid of 5N. I fessed up and pointed out that it was Unauthorised Information so she should pass. 7N was, of course, cold.
I picked up a genuine yarborough tonight, no card higher than a nine, which I can’t recall having before. After the board the woman on my right said she’d only ever had one in her life, and as she looked about 83 I decided to take a photo of it, thinking it was exceptionally rare.
Looking it up it’s a probability of 1 in every 1828 hands - so fairly rare but you’ll likely pick one up every couple of years if you played a club game once a week.
I’ve had at least one this year already.
ETA: I play several thousand boards a year.
Tonight’s disaster:
Sitting South in the 4th seat all vul I hold
S: K
H: AQJx
D: Axx
C: AKQJx
The bidding goes:
W: 2 Spades
N: Pass
E: 3 Spades
S: Double
W: Pass
N: 4 Diamonds
E: Pass
What do I bid now?
Ugh - too much to pass, and assuming a spade loser then a slam requires partner to pull trumps cleanly and may still need the heart king onside.
Unless the opponents are real jokers, partner will have at most 5 cards in the majors, leaving 8. Might be 4-4 in the minors and liked diamonds better, but very likely to have 5 or more diamonds
I bid 5D
Missed edit window again (why is it so short?)
Thinking that East only has 3 spades not 4. Partner has 50-50 chance of having 5 diamonds. Match points I pass, otherwise bid 5D
I bid :smack: 5 clubs. All pass.
Partner tabled this:
S: A
H: 9xxx
D: Q9xxxx
C: xx
I get a spade lead won in Dummy. Now what?
I won’t spoil the suspense. I took the immediate heart finesse. It lost. West led another heart. Ruffed by East. East led a diamond which I ducked towards my Queen. But West was void in diamonds. A long painful series of cross ruffs followed. Down 4.
Passing 4 diamonds was the only winning move. No game was makeable. 30 high card points between partner and I. No game anywhere. A diamond game is ruined by the bad split. This despite the enemy not having the Ace or king of their 11 card suit.
My other big hand this evening:
S: AKJxx
H: AKx
D: A
C: AKQT
28 high card points points.
I bid 2C, partner responds 2 Diamonds (in our system showing no Aces), I bid 2 spades. He responds 3 clubs (weakest near bust response). I bid 4 spades.
Partner tables:
S: xxx
H: QTx
D: xxxxx
C: xx
My only excuse is that I was tired. A heart was led. I called for the 10 on the board, which held the trick. I led a trump to my hand but instead of finessing I plunked down my Ace. Oops. I meant to finesse but then I didn’t. So then there was no choice but to play the King of trumps, felling the doubleton Queen with west. After drawing trumps and cashing my winners, the club ten took the last trick. Making 7 and a great board for us.
5D. When opponents preempt, you have to play partner for something. Sometimes he will not, and you will go several down, but that’s why people preempt.
I would have bid 4H with partner’s hand. Doubler is more likely to have hearts than anything else, and if we are playing at the 4-level, might as well have a shot at the game bonus.
I would have done the same.
If I have worked out the hands correctly (West six spades, K10xx hearts and three clubs), then 4H makes.
How do I avoid losing two hearts and two diamonds?
West is endplayed and has either to give you a ruff and discard or lead away from his hearts and give up his second heart trick.