Some players think: "my mission is defending this flag", but if you go in squads with some medics, C4 or Clays at Flag of this kind of players are not really a problem. Its only a problem for lonewolves
Other players are Statspadder, like our 4 Star-General. That is a problem. He go not to the hills in Karkand cause of getting bored cause 90 % of US-Team playing sniper or supporter and do not try to get any flag. These kind of players dont wait at hotel for the enemy, these players go for baserape from the first second on. The best punish against is not a ban, the best punish is correcting the stats (put some points away).
You've got some good points there. But let me add some of my opinion.
First, most of the time at least one team can't form squads. Why? Dunno, must be some bug. Together with the fact that most people are just sniping and camping, its almost impossible to take a flag. By example, when all flags except Gatehouse are USMC, almost everyone on MEC respawns as sniper or medic (=statspadder).
Second, I have to admit I do baseraping sometimes when i'm on MEC and the USMC team does nothing but sniping. Not like running around in the USMC base, but running up the hill, stabbing 1 or 2 snipers (camping snipers) and going back, off the hill. Since it's kinda hard to explain, I hope you'll know what I mean

Sometimes it's just so f*cking boring when no1 is even trying to take a flag. I know i'm wrong at that point, but look at it this way: the snipers are shooting me, and i'm killing them in an alternate way. I could've shot them from a distance, but the result is the same, isn't it?
Anyway, i'm going

so i'm ending this.
Oh, wait. About the C4/Claymore on flag problem, here's some story what happened to me last time. Some guy in my squad walked into a claymore while capping Square. Just when I revived him, a claymore came falling off the roof, directly in front of me, killing both of us. (guess who threw it?

). The problem is not just claymore on flag, its the claymore spam from ppl who are just lying on the damn roof, waiting for someone to hit their claymore.