Some can, some can't, most don't.
In dealing with commercial accounts, there are a number of pictures that are ordered repeatedly that were taken with a 30D. Most are ordered at 24x36 which, IMHO, that camera does not support.
When I roll up the prints for delivery in a tube, I am at arm's length from them. There hasn't been a single occasion when I did not look at the print and cringe at the lack of resolution, sharpness, and even mild pixelation.
Yet, I have never receive one complaint. It's been all compliments. This is dealing with commercial designers who are professionals who supposedly know quality. Either they don't, or don't care. Neither does the everyday consumer. Quality (and even composition) that will often make you and I cringe makes others smile. There are simply a lot of undiscerning people out there.