Retrieving BitCoin Payments, Confirmation Question
Yes, you can do that. Yes, it will eventually stop sending callbacks.

Expected Response
In order to acknowledge successful processing of the callback the server should respond with the text *ok*. If the server responds with anything else the callback will be resent again every new block (approximately every 10 minutes) up to 1000 times (1 week).

https://blockchain.info/api/api_receive