If you have multiple connections, it may be quite difficult to tell, unless it get's posted in one of the many sites which post daily hacked accounts. Then depending on the service you have, your account may get locked out, you may experience constant glitches, etc.. as you go over your connection limit. I've seen one that allows you to connect, you get the channel numbers and EPG, but none of the stream work, since there are already "x" number of active streams. So all depends on how it is implemented.
Some services allow you to request an ISP lock, country lock, etc.. to minimize the chances that your account gets hacked. But obviously be careful what you ask for. If you travel or use your service when you are away from home on a portal device, this can cause you some headaches also.