Could well. I've heard a lot of larger companies have a policy of only providing references of the form "X worked here from Y to Z" for that exact reason.
I also agree - but then he said something potentially defamatory :-)
However, I think if an employee looks up Shay's details, they will first find his op-ed calling Zynga "evil". I guess if they are concerned about the OMGPOP tweet, then they will be REALLY worried about the op-ed!