They fixed this AWHILE back and it wasnt a lag switch some people did it without even knowing aka guild vs guild. There was A LOT of bugs back in the day their is still an issue with some mechanics I.E. Juggs leaping and making it seem like they are lagging out/untargeteable when in reality its a server issue and not the person pressing something or flipping a switch its been out since launch still have yet to fix it
I am aware of the exact bug you are speaking of. This was after that bug was smashed. I'm not certain it was a lag switch. His dad said that's what he was using.
Either way, if you read about what a lag switch does it seems very possible that you can appear stealthed to everyone else but actually be capping the door. (Even when not the host) nit saying I'm right by any means. Just sharing what I've read.