Lazy Cable Operators...
Have no-one but themselves to blame for uncapping being possible. Letting users bring their own modems to connnect to their networks and not expecting them to play games with them is a bad idea straight away. Not putting the appropriate sanity checks in place is another bad idea.
Haven't seen uncapping on this side of the pond in years to be honest, some cloning but that's about all. Cable operators provide CPEs and control downstream from the CMTS making downstream uncapping impossible. Breaking upstream limits is also impossible as there are limits CMTS wide on upstream usage from a single modem.
The joys of other 'monitoring' as provide by certain 3rd party products sitting behind CMTSes monitoring and policing bandwidths is another dimension in subscriber control.
Any cable company complaining about their evil users needs to consider spending less time complaining and more time making it more difficult to do this. You give people opportunity to get something for nothing or more than they are paying for, of course they will take it. Raise the bar out of reach of most people and make sure that the others get caught.