JCW,
I keep packs of those in travel vest and in our daughters' "go-bag" (formerly known as a diaper bag). When you are on a job in Mexico and your lunch suddenly decides to leave, the last thing you want is direct contact with the portapotty. Same goes when I'm out with my 4-yr old daughter. I don't want her in contact with the bathroom floor let alone the toilet seat...
-Blast