My TV is the last generation 42" EDTV by Panasonic (9th gen). Never had any problem with burn-in; no hint of IR whatsoever. I don't know why, but subsequent models have instances of IR, although they do not have any burn-in issues.
Here's the deal:
Generally speaking, burn-in is no longer a problem for newer generation plasmas. IR can still appear but it is not a cause for concern because IR goes away by itself.
It's hard to say for sure for the LG unit on this thread. The only way to know is to wait for comments from the end-users themselves.
While plasma break-in is no longer considered necessary, some owners still do it for peace of mind, just in case.
The white wash function should be used only as a last resort. The white wash removes burn-in not by whitening the burned areas, but by burning the whole panel. If you use the white wash regularly, you will also be burning the whole panel regularly, which will cause it to get dimmer faster.