IP addresses change but your PCs IP address stays the same. right click ur connection in the toolbar at bottom n it will show u in the details. IP address for internet are given to you by service providers and they have your information on it, e.g. bill paying address and such. If they have enough eveidence to prosecute you and you have been breaching terms and conditions according to ur internet service provider then they can either stop your internet, or the right ppl can fine you.
Best thing to do is when using cracked software is to not let that application access the internet. u do this by use of good firewalls.
Downside to that is you can't update online.