how would you get caught?
Using too much data. Basically if you don't use it a lot then you should be fine but if you do use it a lot you may be charged a lot of money. Tethering on Verizon isn't free.
Basically only use it once in a while and when you are tethering don't stream movies or download torrents or nothing like that.
If you tether a lot it might be worth it to get tethering added onto your line for $30/month extra. This $30/month charge is on top of your smartphone data charge so it will be $60/month to have a smartphone and tethering capabilities.