15 years ago, I used to support VoIP gateways (people used them to sell calling cards so they could provide a local number and then use the VoIP gateway to route the calls over the internet to a gateway in the destination country).
I had one customer who ran his system on demo licences - every 3 months, he would do his billing, then purge his database and re-set all the system clocks to a date a couple of years in the past so it would keep running on the demo licences within their licensed demo period.
Not only that, but the cheeky beggar would regularly log support requests under the terms of his demo licence.....he was such a loveable rogue, though, that I didn't have the heart to tell him to nick off.
Another customer doing something similar in Taiwan was not so friendly, however, and when I told him he couldn't get support, he threatened to use his contacts to have me sorted out....