I was playing today and decided to try getting the armored vehicle ribbon. I ended up getting 21 kills in the tank, 2 more than the requirement, but not enough time in one round. I spent almost the whole round in the tank, only times I was out of it was when it was destroyed and when I had to run to it again. I think the whole IAR time requirement should be taken out, simply because whether you get the 19 needed kills or not,you should get the ribbon. Honestly, if you could get the 19 kills before the 20 minutes, then you're even more deserving of the ribbon.
play on 64 player maps with 16 people.
I was actually on a 32 person map with 16 people at the time too, it was annoying to find people to kill and the round ended because the other team ran out of tickets before the 20 necessary minutes.