They’ve been more aggressive calling those plays dead if the defender would have a clear line to the QB. From the defender’s point of view, if you’re going to lose 5 yards anyway, might as well take the free hit on the quarterback.
arena FB lets the man in motion move forward before the snap. In fact they don’t seem to care much if the guy is a yard past the line of scrimmage at the snap.
As does Canadian football. I’ve wondered how well they time it, and how often they wind up just a little offsides.
Offensive linemen can’t move but the QB is allowed to bounce around all he wants. Explain me that.
Also explain me why sometimes they blow the play dead on defensive offsides and sometimes they allow it to go on.
As Chisquirrel notes, if a defensive player jumps offsides, and looks like he has an unimpeded shot at the quarterback, the play will often get blown dead on the spot, to protect the QB. Also, I believe, if a defender jumps and makes contact with an offensive player, that’ll also lead to the play being stopped.
Because the QB isn’t right in front of you. The QB isn’t as distracting as the guy you’re facing. It doesn’t have the same impact.
Now sometimes the QB can draw an offsides if he’s clever (or the defensive lineman is gullible) but it’s much harder for him to do that than the guy directly across from you.
The frozen stance rule applies to players in the three-point stance. They have to be like statues. Wide receivers and running backs behind the line can jiggle somewhat, as long as they stay planted (are not in running motion). When the QB is under center, he can look to the sides, but (at least in the past, it may have changed) he cannot do a forward head bob such as would suggest that he is taking the ball from the center. I seem to recall having seen the QB back up from under center to shotgun, but I think there is some rule about how abruptly he can do that.
Quarterbacks get much more leeway in terms of false starts, but I’m pretty sure I’ve seen a QB actually called for a false start once. Something about simulating the snap before it’s actually snapped.
But some of the leeway is obvious, like if the QB has to shout the cadence because of crowd noise, his head bobbing as he shouts may be unavoidable.
Chisquirrel answered this already, but not directly in response to you so I figured I’d clarify:
No, if the defense jumps, doesn’t touch the guy, and goes back into position, if an OL reacts to it, it’s a penalty on the defense, not the offense. That variation is new-ish (post-2000 I think) and it’s specifically intended to discourage trying to bait the OL into false starts.
A couple of years ago, they started flagging the QB for a false start if he moved his hands as though he wanted the ball. It may have even been a recent rule change. They move all the time now, so maybe they changed the rule back. If this were GQ, I’d Google it, but I can be lazy here.
Tom Brady was penalized for a false start in Super Bowl XXXVIII against the Panthers in 2004.