I've seen this several times and not even just in swarms. Sometimes it's just players being lazy.
Most recently I've played a few games (in tournaments) where someone has revealed a maneuver, saw that the ship would bump and then picked it up and moved it by hand in an approximation of the turn until it bumped.
I was flabbergasted! I could not believe it.
Definitely one of my pet peeves in X-wing.
I once had an opponent assume his X Wing bumped my ship, instead of flying passed over it, range 1 into its arc, so he picks up the ship and moves it. At best, it BARELY didnt make it, but I'm fairly certain the 2 Fwd flew passed. Bah, then when I asked him to put the ship back and measure, he continued to nudge the ship until it didn't make it. I mean, once he picked it up, there was no way to accurately measure anymore, but it was quite annyoing as it was clearly a move in his favor. Woulda put his Wedge range 1 of a Tie fighter.
Obviously I let it go, and yes, it did contrubute to my modified win instead of full win.
That all came off a bit meaner than I wanted . Sorry! Just wanted to share and let players know that you really NEED to measure movements and not assume, cuz our eyes can measure wrong. I know I'd feel bad if I did that to my opponent. At LEAST, ask your opponent if it is okay to just move the piece. Both players should be in agreement or you are not playing fair.