I'd heard that having gnooboos depended on a wedding arch on the property - I was pretty sure that you got toddler gnomes starting once you had a Sim wedding with a wedding arch on the lot, and after that it was automatic. (I'm still getting toddlers occasionally and there hasn't been a wedding on my property in quite a while, but the rate seems to be slowing down, maybe?) Interesting if she got it to work by putting the gnomes under the arch, even without a Sim wedding.