Did cancellation policy change for drop-in visits?

I knew that dog walking bookings could be cancelled at will by the pet owner without having to pay a cancellation fee, but I think drop-ins used to invoke a fee. I never understood the difference. The sitter is still blocking time unavailable to other clients in each case. After looking around for policy on the site, it looks like walks or drop in visits can be cancelled at any time, even the same day as the booking, without a fee. Can someone confirm that this is the case? That drop-in visits cancelled on day of no longer invoke a fee?