Actually, speaking for myself I only knew that sometimes I strafe a tank and I get an assist, which told me that I was doing (some at least) damage. I've never gotten a kill on a tank (that I know of) and would have probably thought it odd that I had if it didn't happen until later.
But I kinda doubt that everyone who strafes a tank is hoping to steal a kill from a more deserving player. I'll bet there are many like me who up to this point strafe them because it's there, and seemingly not paying attention to me so I can get away with it.
Grue