after what i know and have tryed pmove is a client side setting not a server setting. Pmove is not a cheat but it will make the game feel MUCH different for the player. he will feel like he is leaning much faster and he can shot faster. BUT it is all client side. I feel pmove gives some players with some grafic card a big advance (it wont be working smooth with all grafic cards)
i used pmove for a long time before it got "famous" and ive never been told that i lag/warp at all. I used pmove because i had a shitty pc and a shitty grafic card. and i got a better gamefeeling with pmove on.
(i havent used it since extmod)
i found this at a quake3/sof2 site
http://ucguides.savagehelp.com/Quake3/connection.html