It depends on what the definition of abuse is. I have seen people drop their DSL/Fios/Cable service for using just their wireless phone, this is not a bad thing unless you are downloading tons of data (Movies, Music, etc).
The casual user that is checking their emails and sending small or medium size files should not feel as if they were the ones abusing the system.
I mean seriously, if you really need the DL 5GB or more of data per month, then you need a home connection. Not only are you wasting bandwidth, but you are also killing anyone else connection...