Oh no, trouble! That's the worst thing that could happen to someone! Getting in trouble!
People should stand up for themselves more, you deserve to be paid for your work. The client is the only person who should be in trouble. Don't be afraid of trouble.
You can't just sabotage your product because you didn't get paid. That just creates two wrongs that do not simply cancel each other out from a legal point of view.
There's a legal system to settle payment disputes. Using it is the civilised, and safe, version of "standing up for yourself".
Many service providers will put up nondescript error pages when the account isn't being paid. That's somewhat safer, but might not apply here: service providers are refusing to continue service. They're not changing a product that was already delivered.
Are you sure it's such a good idea to go around looking for trouble like this?
There are plenty of legal recovery avenues without going looking for trouble and pretending it's just standing up for yourself - a defense which will go nowhere in a felony hearing.
People should stand up for themselves more, you deserve to be paid for your work. The client is the only person who should be in trouble. Don't be afraid of trouble.