What to do if crockery made impure by a dog is not washed according to the Sunnah in a non-muslim café?

My wife and I go to a café run by non-muslims (there are limited choices where we live unfortunately). They have a separate bowl for dogs, so that it stays separate. But my wife observed another customer letting their dog drink water from a glass intend for humans to use. The glass got collected and washed in the dishwasher, but was not cleaned once with soil first. Now we are paranoid about other customers letting their dogs make the crockery at the café impure, with no way for us to purify them. We could stop going to this café, and seek out a Muslim run establishment, but even then you couldn't guarantee that something made impure by a customer's dog would be spotted and washed with soil (and expected everything to be washed with soil on the off chance it was made impure seem impractical and unreasonable to demand.) What does one do when you can't reasonably follow the Sunnah on purifying crockery made impure by dogs?