It would never have to occurred to me to be bothered about a parent parking there, but NOT using their pram!

As others have said, I see those spaces as being for people with small children. Whether or not you use a pram, it's still difficult, and potentially dangerous to weave through a car park with a baby/toddler. Quite frankly, I think it's ridiculous and petty to think that a parent MUST use a pram if they park there.