1) If you're daft enough to try and register the cracked software, they'll definitely know.
2) If the software automatically checks for valid, purchased serial numbers with the company's website database, they'll almost certainly know.
3) If you use an old crack with a newer version of a program, they probably won't know, but they might pretend to.
The good news is, the chances of them doing anything about it are absolutely nil, unless you're pirating their stuff on an international scale and making tens of thousands of quid out of it.