Both of my boys `gave up`their naps by the age of two. In hindsight, though, I gave up enforcing them. My oldest daughter was a better napper and still napped consistently until she was 3 1/2. Even now, she has a few quick zees in the afternoons every once in a while.
I am definitely more strict with naptime rules now, with the daycare. For one thing; playfelt is right when she says that these kids are almost never getting a 12 hour night time sleep. For another, they play so much harder here than at home, that it poops them right out.
I think that if you are firm, and consistent in returning them to the nap place every time they try to escape and reminding them what the naptime rules are; you will see success. And if someone is shrieking and being loud, they will nap in a different place, even if it is at the end of a hallway. You can treat it like a privilege. When they show you they can be quiet, they can join their friends during quiet time.