What could operators do?
That's obvious, start treating your customers like human beings and not just idiot money suppliers.
At work we have a few SIM cards from a German resell operator. We need it inside a M2M solution. Therefore we only need GPRS connections to the Internet. (Don't worry, it's nothing anybody would mind failing)
However we have a few SIM cards from which we cannot initiate any connections to the APN. Mind you it's always the same APN and always the same device, but for some cards it works, for others it doesn't.
I've tried to explain that to their customer service, but all I got was some excerpt from the manual and a hint that my device which is a Simcom SIM900D (go on Google that) might be SIM locked...
Another German operator decides it's OK to cancel contracts of customers using IM or VoIP, even going through great lengths of trying to filter it.