Current record for fish living in a bag that I have seen was two months. They were killifish, an Aphyosemion species as I recall. They did get pretty skinny, though.
Generally, a week is not a problem. Certain types of fish that are sensitive to ammonia may not last as long. I have bagged fish the night before an auction, driven 1-3 hours to the auction, had the bags sit on a table for 5-6 hours before being sold, and then they usually sit in a styro for another hour or two till the person leaves the auction, at which point they are going to be another 1-3 hours getting home before they even think about putting them in a tank.
In your situation, I would get a pad of ammonia absorbent Polyfilter, cut a small 1/2" square and put it in each bag. Even ammonia sensitive fish will live a week or two with this in the bag. That small square will suck up a lot of ammonia.