Don't assume. I've dealt with my fair share and I know the smell from a mile away. But all you can really do when you find one is clean the enclosure. That is what I am trying to say. Even if he was not on vacation, most of us are not watching our snakes 24/7 to clean it up immediately. He would notice the regurg as soon as he would notice it.
Either way, a snake is extremely unlikely to regurg after 7 days.