I also have a VT30 and use it for gaming. After 3-4 hour gaming session the HUD from that game is usually visible as IR but after watching a film it goes away. Sometimes if I play the same game day after day the HUD gets burned in for a bit longer (sometimes a few days) but it always goes away eventually.
I owned a G20 plasma before my VT30 and did get permanent burn in from my FPS counter (because I was using it in every game, now I set it to move position every hour). But it took hundreds of hours over the course of months before I started to notice it.
Source: Gaming/HT PC, i7 3770K, 16GB DDR3 2400Mhz, 2x GTX 980Ti SLI, MPC-HCx64 w/ MadVR & SVP frame interpolation
Display: Panasonic VT30 55" Plasma ::: Receiver: Denon AVR-1910
5.1 Speakers: Behringer B215XLs
Subwoofers: 4x SI HT18 D4 open baffle powered by iNuke NU4-6000 (1 driver per channel at 2ohm)