Silly Laundry Question

I have several sweaters and t-shirts that are just plain 100% cotton that the laundering instructions are hand wash/gentle cycle and then lay flat to dry. My question is - would it be so horrible to put them int he dryer on low temperature to dry? Because otherwise I've got a dozen tops hanging all over everything and then I have to iron them and ironing t-shirts is a bit ridiculous to me. They're plain. There's no decoration on them. Is it a shrinkage issue since they're 100% cotton?