Here's my take on GMO:
We are good at selecting for the traits that we want in crops, etc. As for other unintended gene products, well, that's another story. It probably wont show its effects until much later.
Having worked in both clinical and research settings, I can tell you that a healthy dose of skepticism never hurt. Uninformed fear, however, is an utter nuisance.
It seems rather unlikely, though.
Especially regarding that much more genes change in artificial selection, so - from a gene standpoint of view - I would assume that the more genes change, the bigger the risk by that logic. ;)
Though, I totally agree with you here.
It's not that it's unlikely. It's that we don't know and probably will never live long enough to see the effects as the selected genes interact and evolve with the original species.
Eukaryotic gene interactions are a lot more complex than what can be observed in prokaryotes. Take humans, for example, we have so many products from ~20K genes. It's not as simple as transcribe a segment, translate it, and boom product.