Here's an example- send a command - it could be that you "LB is up" or "run!" or "pinch!". Now send the same command 10 times as quickly as you can, potentially with a sound effect.
I have yet to see anyone ask them to "shut up", as anyone has been far more polite. However I very much doubt that spamming like this is helpful, I haven't seen in done by any skilled players in any other game, any I have yet to see anyone thank someone for spamming like the case above. Also- in those other games- which were designed for PvP- chat was reserved for the lead(s)- but that's a completely different type of game- then we're talking premades, and everyone in the alliance adheres to certain behaviour or gets kicked. I don't see that discipline happening in FL in NA.
Now- when someone doesn't spam, it's a far different story, they do get thanked and/or given commendations.