my DF's mother made an account for Jonathan without us knowing but she gave us his little passport thingy as a gift and said she would put money in every week and we could add to it when we want. She never asked us but she said she also needs the birth cert. I dont think you are being irrational at all, the way they went about it was wrong and the fact you had expressed that you didnt want that should have been enough for them to back off. Also the account our son was given is not allowed to accessed by anyone other than Jonathan if thats what they are worried about.