I use the little booties they provided and I ended up with some funky lines! Next time I go I'm just going to step in them, not wear them. :) also, make sure you wipe the back of your ankles, mine kinda got a lil darker than the rest of my legs. -_-
Boshena's comment: Yes, booties can make the tan messy. I prefer to put some barrier cream on my fit and then step onto sticky feet. that way feet usually tan fairly even and sticky feet keep my feet clean underneath.