I understand your pain, even though this has only happened to me twice. Most of the time they warn of their intentions before letting explosives fly. What makes matters worse is that they expect to be respawned, when there have been a couple of instances where that wasn't that case. They then begin to bash the game because they failed to adhere to a safe minimum distance, etc. Why should a game reward bad decsion-making and sportsmanship?
My problem is more with TKs in general, I wish we had something to fight back against TKs. Like kick votes or auto-kicks. I understand why people will not support an auto-kick for TKs when accidents do happen, but honestly if you end up putting more than 1 round in a friendly target you become more of a liability than an asset. Someone that just can't seem to get hits on target or kills is preferable to people that TK because at least you didn't lose because someone couldn't tell the difference between a security/insurgent kit (basically blind) or completely disregards the experience of others. Either way a skill and mindset change would be in order for them.