[jonknee]

AirBnB goes to a lot of lengths to make sure you at least have to book through them the first time. They filter out phone numbers and email addresses in messaging, even if you try and get clever (like spelling out phone numbers).

[brobinson]

You can split them into two numbers which look like zip codes (in the US anyways).

555-123-1234 would become

"55512

part 2

31234"

I've done this to get around the issue when trying to get in touch with the property owner.