You can say that again.
Regarding tethering, acquiring a new mobile customer costs carriers more than $600 on average. (marketing, equipment subsidies, setting up the account, etc.) Replacing you is expensive, so they are most likely to send a warning letter first in attempt to keep you as a customer, but get your usage in line with their expectations.
The carrier -could- just terminate your account without warning, but probably won't. In telecom, services are usually only flat out terminated without warning for cases of fraud (any sort of shenanigans that will affect them financially, costing them actual dollars) or blatant abuse (using the service in a way that is so out of control it poses an immediate and serious risk to network availability). Tethering doesn't fit either of those criteria, so if it does start to annoy VM, I think warnings and threats will be the first step.
Technically you're doing something they don't intend you to do, so you are taking a risk. I'd keep that in mind, watch for any warnings, but not really get too concerned about it.