This would be very cool and would make tanking very different in-game. I've read stories of tank crews being confused, or having to fall back while being pummeled by things that didn't penetrate their tank. (like a 20mm flak against a Cromwell)
right now the only thing that does this in-game (unintentionally) is shooting a bofors at a tank. the big black puff is almost like suppression. as a matter of fact, it's sometimes a problem for me as a tanker to encounter a bofors. I've actually had to fall back a few times to get my situational awareness back.