To find guests bringing dogs to our B&B without informing us beforehand unbelievably cheeky?

[Woolysheeps]

We run a B&B in a rural area in the Scottish Borders.
We do state we are 'pet friendly with additional charges' on booking platforms.
I would say 70% of our guests bring dogs but of this 70% only 10% actually inform us beforehand and enquire about charges and where the dogs are allowed etc. Most just turn up with their dog and walk right in. Some bring 2 or 3 dogs with them and don't bat an eyelid when I say 'you didn't inform us you were bringing a dog....'. Not a single guest who has brought a dog and not informed us has ever mentioned the additional charges specified online and aren't happy when we bring it up. It is making me want to remove the 'pets allowed' feature as I feel it is being abused.
So, my question is, if our booking platforms say 'pets allowed with additional charges', AIBU to expect to be informed beforehand? Would you inform a B&B beforehand if you were bringing your dog?

People don't read text in detail. If you are using a platform that has a filter category for accepts dogs then they won't read the fine print. If you are not struggling for customers, I would drop the dogs welcome and just have it in the message that dogs might be considered for an extra fee, then they would only pick it up if they bother to read it properly.