Only IF Verizon catches you using it..but this is unlikely. As long as you don't UBER-Download while tethering, you should be ok.
I wouldn't worry about usage too much. I am an internet radio nut(I let it play while I sleep a lot, plus use it during the day..my data usage goes over 7gb per month sometimes.. and has been as high as 12gb in the past. I've had no questions from Verizon so far(knock on wood).