A lot of them use a phone home/license key model... so it will stop working if you don't pay for the license. Where they don't, ya it's basically a trust system

A lot of them use a phone home/license key model... so it will stop working if you don't pay for the license. Where they don't, ya it's basically a trust system and most big companies would rather just pay the license fee than expose the legal risk of using software illegally.