I'd expect anyone spending the amount of money on such a TV to actually read the spec.
If they didn't then they are fools
i have read dozens of reviews and not one of them has mentioned this. i have read the specs on the product page if I remember correctly but it did not set off any alarm bells. I have never had to use arc or earc with my other tv's. I have / had tv's from Panasonic, Philips and Sony and not one of them had such horrible lip sync issues as the LG. I dislike earc / arc for several reasons (less hdmi sources, the master (tv) - slave (reciever) thing etc. I never ever took into account that i would not have another option than to use earc (and that no dts passthrough would be an issue)
by the way: even the seller where i got my Marantz told me, do not use arc or earc, it's garbage...
little did I know that the garbage was in fact the Bx that i bought.