They’re not supposed to call the police when they’ve been robbed? Theft of service is a crime is it not? If the police aren’t doing anything that’s the problem

I'm speculating here, but I guess it boils down to the amount of money involved combined with the absence of threats or violence.

In general it makes little sense to spend resources investigating a non-indictable offense where the perpetrator is unlikely to be found in the first place and even if they are found the cost of even finding and processing then is much higher than the monetary damage they caused.

If it’s becoming a big issue, why not ask people to put a credit card on deposit when they sit down?

Restaurants that see you pay after the event are really in the experience business. Putting a card down takes away from the experience.

That's not a problem, as such, when all restaurants are doing it, but it's hard to go first as it compels customers to go elsewhere. Which you especially can't afford when dine-and-dashers are already hurting you.

It will likely go that way eventually. But it's a big risk and will no doubt claim some casualties when it comes.