I can't find anything on how the gas company handles this situation.
That's because they don't publish what they will do, otherwise people would abuse the system even more.
What they will do really depends on the gas company policies.
When the tech shows up to turn on the gas, he may simply scratch his head wondering why they sent him out to turn of the gas that was already on. Maybe he'll think to himself "Good thing nobody found out I forgot to turn off the gas". Maybe it's too much paperwork and he'll simply report that he turned on the gas.
On the other hand, maybe he gets a bonus for each person he catches tampering with the locks.
There's no way anyone here can predict what will happen.