None at all. I walk in, I look at what's on offer, and if they don't have what I'm looking for, I leave without buying anything.

There's a legal obligation not to steal, of course, and if you want to call that a contract I can't stop you. But if you're claiming there's an implicit contract to buy something when you walk into a store, you're wrong.

Now, if I was walking into the store all the time just to stand around not buying anything, that would be trespassing, and if they asked me to leave their property I'd be obligated to follow their wishes. But if I'm walking in in order to buy some bananas, but they're nearly out of bananas and the ones they have left all look bad, then I'm perfectly within my rights to walk out without buying anything.

In what way are you claiming that the grocery store analogy holds to adblocking on Youtube?