The testing centers I've been to for some online tests do everything but a full body search to insure no cheating.
I think it would be the prejudices of the exec doing the hiring. They may feel as if on line courses are not “real learning” in the sense of how they had to do it.
There is definitely a good old boy network when it comes to certain fields and companies where the HR individual would not consider a graduate from a college with a strong rivalry with his own.
I actually believe the online learning will eventually take over ALL levels of education from first grade and up.