I can absolutely agree that LiPo's are far superior to NiMH in every way, but even you have to agree some people just should not be trusted with them lol
My argument is simply that if someone is already set up to run NiMH, the first step would be to upgrade their wiring and install a MOSFET before making the jump to LiPo.
It costs you about $40 to rewire a gun and install a MOSFET and then you're getting the max out of your batteries. But if you don't have a LiPo charger, it costs about $140 for a charger, MOSFET, PCB and fuse to safely run LiPo.
So you'll save $100 if your happy with the performance you get from your current NiMH batteries on the MOSFET, and if not, there's nothing stopping you from finishing the conversion to LiPo.
But if you already have LiPo from RC cars or just want to start out with LiPo, there's no problem as long as you run them safely.
It's a pet peeve of mine to see someone with a stock ARES or something running a buffer tube 3S LiPo with no circuit protection, just because some site said it was "LiPo ready". You get a short in that gun, and that buffer tube becomes a flamethrower