People instantly bailing out of a BA-64 is just as wrong as instantly bailing out of a Tiger/IS-2/takeyourpick.
It's something gamey across the board. A tank crew would be pretty powerless to stop someone they noticed had just slipped around their flank with a Panzerfaust, but in RO you can hop out and pistol/SMG them down. It's an across the board problem and though I don't support super-satchels, I can't support people saying 'don't do it' unless they refuse to jump out of their tank when they have been legitimately out-flanked or snuck up on by infantry.
But, yeah, painting targets with the BA is solid if people actually do it