DD is 18 months and likes to put her toys in her mouth; so her new Duplo set (I took out the smaller pieces so there's nothing that would constitute a choking hazard) and anything similarly sized ends up in her mouth frequently. I don't mind this particularly, the way I see it she's just investigating her toys and her mouth, she's always supervised and I don't leave anything around that she could hurt herself with.
My parents mind her two days a week and they have a massive fridge magnet collection. DD adores playing with them, taking them off the fridge, putting them back on, putting them in her trolley and wheeling them around the house, and. inevitably, putting them in her mouth.
Because of this, my parents are investing great effort into telling DD not to put things in her mouth. I don't really think it's worth teaching her that at this stage as it results in a constant stream of 'No!' and 'Ah-ah!' which she just finds funny and ignores - or she'll say 'Ah-ah!' herself as she puts them in her mouth. I'd rather remove inappropriate things from her reach and let her mouth the safe stuff, and save the discipline for more important issues. She's still very little, after all.
I realise that I'm in no position to tell them how to babyproof their house, or to insist that they allow her to chew their belongings (especially when they're not designed for kids!), but I do think it's confusing for DD to have two totally different sets of rules enforced by different people.
Am I being too lax?