Yes, so he did and thanks for pointing that out. I think I was keying into the 30 minutes idea. Thirty minutes isn't very long for, say, a thick chicken breast. If somehow the meat isn't cooked through and sits awhile cooling, that could be a problem. Maybe I'm just paranoid. I'm really interested in the method (sealing in the bag, the meat sucking up the juice, etc.). Just wouldn't want to take a chance with re-using the marinade.
The various links I've found say if you boil used marinade hard for five minutes, it's safe to use as a sauce (i.e., with the meat it was on) but then wouldn't be much good as a marinade for other meats due to the changes boiling makes.
I'm with you--I err on the side of caution. Food poisoning is no fun and if there is the slightest concern, I pitch whatever it is.