Sure. But **Brayne Ded ** and Sitnam were discussing specifically mediaeval armor, so I used (late) mediaeval examples.
Ever since I found out about this I’ve been noticing this everywhere and it drives me nuts. Even if they weren’t meant to speak due to other reasons (the extra looked good but had a bad voice / writers wanted the extra to look distracted / extra forgot their lines but the take was otherwise perfect) it still looks like they’re being cheap which will still take me out of the movie.
I apologize if it wasn’t clear I was referring to both ancient **and **mediaeval armor.
Likewise, I don’t want you to get the idea that I think munitions armour was the only mass-produced armour.
Actual motorcycle sounds are often dubbed over with the sound of a high-revving inline four-cylinder engine…even when the actual bike is just a big two-cylinder engine. The 2003 Italian Job did this…twice. First, with Seth Green’s Ducati 748:
What a Ducati 748 really sounds like
And again later with the BMW R1150RTs used in the Mini Cooper chase sequence:
BMW R1150RT in The Italian Job
What an R110RT really sounds like (“gassy sewing machine” is an apt comparison)
This happens a lot in movies, but most recently in Hobbs & Shaw so I’ll use that as my example. I hate it when characters are speaking to each other, shouting even, when there is literally no possible way for the intended target to hear it. In H&S it’s the Rock being underneath a helicopter and about 40 feet off the ground yelling to the driver of a daisy-chained car who is 40 feet down and 40 feet in front of him. “Do it! Now!” and he does it.
It never ruins the movie for me, but like the thread said, it does briefly take me out of the movie and prompts a “yeah, right” out of me for a bit.
An even more blatant example is in the made-for-TV movie Birds of Prey (the one with David Janssen). It seems they cast stunt men for the bad guys, but I guess stunt men can’t have speaking roles or something. Could be Guild rules, could be it just cost too much. So when the bad guys have to talk to each other, the camera frames on the one NOT speaking. I assume they used voice actors for the actual dialog, who are probably cheaper.
If it is union rules, it’s a stupid one. Because the (probably) stunt men were acting, even though they just didn’t speak.
There’s an actor, I can’t remember who, who makes a habit of prompting dialog with actors who would otherwise be extras in order to get them speaking roles, which IIRC helps get them SAG cards. Obviously, the director and the editor have to go along with it, but still.
Spoofed in Shazaam, when the hero and the villain are both floating hundreds of feet about the city, and about a hundred yards apart. The villain starts monologging, and the camera cuts to the hero, who’s all, “What? I can’t hear you! Are you trying to say something to me?”
…seen first in Kung Fu Panda 2 when the same thing happens 
It might not be due to them being cheap. It might be due to Screen Actors’ Guild rules about speaking roles in movies. If your role is a background character (usually meaning not having any lines) then you don’t need to be a SAG member.
SAG membership is expensive for the first payment, currently $3,000; it does come with very cheap medical insurance payments afterwards providing you keep working, so it’s worth it for a lot of jobbing actors. But it’s not helpful if you’re just doing this as extra work and have insurance via your regular job, or you’re fairly sure you won’t get enough work for the medical insurance requirements (82 days per year, can be theatre or print ads or anything like that, not just screen roles; or alternatively earning $13,000 from SAG productions over the year).
There are limits to how many speaking jobs you can have without having to apply for SAG membership before being allowed to work on SAG-affiliated productions again (which is almost all professional productions).
(I’m not an actor; I’ve been researching this for something I’m writing).
So bizarrely it’s another area where privatised healthcare has an effect.
“These pretzels are making me thirsty.” 
No it was the new format - with the state shape between the letter sequence and the numerical portion, and with the color inversion where the state name is on top.
“These pretzels are making me THIRSTY!”
Or as Montserrat Caballé recounted about the first time she was cast as the dying-of-tuberculosis protagonist of La Traviatta: “have you seen pictures of me?”
Isn’t TB one of the diseases where you can actually look fairly healthy before you die? Thinner than usual, yes, but you could start out overweight and still die of it overweight, just less overweight than before. It’s one of the reasons it used to be used in a lot of old movies.
When a character is fast asleep in bed and the phone rings, and he turns on the bedside lamp before answering the phone. Not only would nobody turn on the light if he didn’t have to, he doesn’t even squint when the light goes on. Ever.
“These pretzels are making ME thirsty.”
In the opposite vein, can’t remember the title but there was a scene where the protagonist calls his girlfriend. Cut to her asleep in the dark and the phone rings. The bedstand lamp snaps on, she rolls over in bed and picks the phone up to have a muzzy conversation, then rolls back over as the light snaps off.
I thought at the moment it was a really egregious error but it turns out later she was an agent and the lamp-snapper was her handler.
She didn’t squint, though. 
These pretzels are. Making ME. Thirsty. --Christopher Walken.