Are 4G sim cards swappable?

[blackmannx#AC]

I use an adaptor when I take my sim from my nexus to other devices and as much as I swap devices I havent had an issue.

Last week:

Nexus, rezound, Nexus, Xoom, New LG, thunderbolt (to update to gingerbread) back to nexus with a few mins in a Razr to update that devices software.

brought this awhile ago

Amazon.com: Micro SIM Cutter, Converter with 2 SIM adapters: Electronics