That is the worrying thing, the kid was too young to even care. If it had been an annoying 5 year old constantly yammering on about wanting it and badgering the mum to try one more time then it would at least be a bit understandable, but for a 5 month old?
Honestly, if it were a 5 year old, I'd be more concerned about the useless job they were doing as a parent to not be able to tell said sprog "No" and be done with it. I know kids don't always listen, I know they can get downright stroppy about it, but that's part of the job of a parent. And I speak as the parent of two "we're in double figures but not quite teenage yet" sprogs. Who do know what the word "No" means. And they also know that incessant arguing of the point will result in the playing of one of the Dad favourites, such as "going home early", "no you don't deserve to stop at McDonalds on the way home" or the more serious option of "You'll lose your phone for a week"