I hate to keep harping on this but I'm going to anyway...be aware that there are some TSA people working the security areas that will not accept anything other than a qt. sized ziploc baggie. Some even go so far as to have the correct baggies there for you to use. But, most don't.
So...while some have been able to use sandwich bags, it is not what the TSA is asking you to use. Just don't want someone to come back here and scream because a DISer told them they could use a sandwich baggie instead of a qt sized one, and the TSA people took the stuff away...not a good way to start a vacation.