Sigh. My parents. I love them, but this drives me bonkers.
They waffle. We'll call them up and ask them something: "Do you want to do this with us on X day?" "Can you watch the boys on Y day?" "You mentioned getting this for DS for Christmas. We found a neat one for a good price. Do you want us to get it for you?"
The last one happened this weekend. My parents had mentioned getting DS1 a certain item for Christmas. (The boy is just very difficult to buy for ... ) We had had the same thought, but bowed out so my parents could do so. Then they changed their minds and were going to do something else. At this point we had mostly finished our shopping (especially "main" items), so we figured he just wouldn't get it. That's OK. An idea for next time.
Then DH and I were shopping this weekend and saw the item. On clearance. For a fantastic price. And it was a particular variety that we hadn't known existed, that DS would particularly love. I called my mom and asked, just to be positive, if they were sure they didn't want to get it for him. (We would have picked it up and we would have paid them back.)
Mom: "Oh. I don't know. We're thinking 'this' and 'this.' And maybe 'this.' " (hems and haws and does not seem very interested)
So I say, well, no worries, and end the call. Then we find an additional present for DS2, something that again we didn't know existed, and really want to get it for him. This evens things up for the boys. We decide that, hey, Santa will be generous this year.

(We do not go overboard with presents. The boys get 2-3 and stockings. This makes it 4. Huzzah.)
I'm talking to Mom later and tell her we got DS2 something extra too, so it nicely evens up. And she's disappointed. "Oh. I thought we were going to give that to him."

Uh, you waffled until we just found a way to do it ourselves. You never once said, "Yes" even conditionally ... or things would have been different. I'm not a mind-reader.
It happens with other things too. They'll waffle on plans, so we'll make other plans. And then discover they made arrangements to do it after all.

And are upset/disappointed that we're now doing something else. "But you asked us to do X ..."
I love them. But ... ugh.