Is your TV a plasma? If so, then I'm guessing the person was concerned about burn-in when playing 4:3 aspect ratio games. But, this would be no different than watching standard definition programs on the TV.
thats what i thought but the tv repair guy said it was bad and i rember asking the sales people about it (but thats not always a legit source) but its a rear projection hd tv 65 in and i have been playing games on it sense we got it do you know of a source i can print out and as proof that it doesn't harm them?
Should be fine on a RPTV. Something like an older CRT FPTV would not be so good. And the reason it's different then other sources is that there are stationary objects on the screen (I.E. the score or in an RPG the bars with your health and what not) on newer tv's not a problem though.
If it is a CRT projection, be careful of burn-in. A friend of mine had a diamond series Mitsubishi and burned-in the gun sights of the game Quake. The gun sights were stationary and bright white. the back ground of the game was dark.
Note: He also played the game for hours a day for over a year. And you could only see the burn-in on very bright sections of movies.