I'd say it's a real concern, if she really does spend a lot of time on shows that have a static logo. Personally, I never worry about it, but i'm not a worrier. If it was something that made me think about whether I should be watching this show or that show for any specific amount of time, or I just had a niggling doubt about whether I would run into problems, I'd go with a trouble free set. I gotta say though, if you're concerned enough to ask about it in detail on this forum, I'd say go LED. The benefits of plasma are going to be nil for watching those shows anyway. Life is too short to be worried about IR!
Ha ha, where were you when I was asking about IR! Ha ha
As far as aman74 questions, in my brief experience with my new plasma (350hrs and going), I'd say IR is inevitable with any static image, how much and how bad varies. I HIGHLY recommend turning Pixel Orbiter on, it helps a lot, doesn't stop it, but instead of leaving a perfectly etched copy of a logo on the screen it just leaves more of a blur in the area the logo was. I play a lot of games on mine and I've seen the drastic difference between it set to Auto (aka off) and On. After every play session (1.5-3hrs) I tend to go out of my way to find IR, by loading up a pure white slide, sometimes no IR, other times faint grey blurs/blobs, but this is me being SUPER paranoid (which sounds like you are too).
But I've only actually noticed this once in normal viewing, which I'm afraid to say was on network TV. After watching an episode of Agents of SHIELD for an hour, on some really bright white commercial after the show was over I could make out a pretty larger blob where the "ABC" stupid snowflake logo had been during the show. I didn't notice it during other commercials during the show though, and I was done with the TV then, so I ran the screen wipe for 5-10mins and it went away.
And that was just an hour show, and that got IR quickly, I'd say if your mother watches a lot of tv during the day, I personally (and I'm not an expert) would go with an LED. I think a plasma in your situation would bring you a lot of stress and heartache, as it has brought me in the first few weeks of ownership. I'm learning to live with mine a bit, and not be so anal about it and decided to keep it, despite how bummed I get any time I find some larger IR on the white slide. But I've learned that I'm going WAY out of my way to see it. BUT I'm also the only one who uses the TV so I can control how much it's used and what is done to correct it. Also oddly enough, games seem to be a lot easier on the panel than network/cable TV. I mean TV channel logos seem to IR more easily/badly. as with a game the images are smaller (less area to IR) but also going into menus and cut-scenes and what not fairly often, along with the pixel orbiter on mostly causes very little IR I've noticed. I've played one game several times in 3hrs+ chunks with the orbiter on and had no noticeable IR, but the one time I left it on "Auto" was some of the worst IR I've ever seen, clearly had various text very readable on there, as well as various lines/bars from the HUD as well, it made me sick to my stomach. I ran the swiper for 15mins, it was better but still very read able (on a white slide) so set the slides to run over night while I slept and by the next day it was fine. Still stressed me out a lot, and it sounds like you have less control over your set, so you may want to avoid situations like this.