I encountered this earlier and (narrowly) won against it because I had a LB on MNK. Tackle > LB to kill them. And then... I picked up the medals and kited THEM around our base with Fists of Wind and Shoulder Tackle, same way they did for us, and timed them out.
It's a really lame strategy, and people already suggested force people out of spawn... and I can see it becoming a problem in the near future with the Vuln change once again. (It needed to stay severe.)
If you're a fuckwad that does this though; stop ruining PVP.