Won a trip for 2 to Ireland back in 2002. I think it was originally for 4 days 3 nights. I asked the sponsor (through the Sweep Administrator) if I could extend my trip IF THERE WAS NO ADDITIONAL COST TO THEM. They said fine and I spent 12 days there total. So the first 4 days/3nights were on the Sponsor as well as the airfare to and from. It worked out great. As long as it didn't add to the cost of the prize (and it didn't), I don't think the Sponsor cared. They were going to spring for 2 round trip tix on Aire Lingus anyway. So, go for it. It does not hurt to ask. Just don't ask for pie in the sky!