I hope this doesn't come across as morbid, but I wish someone had pointed this out to me when my kids were babies...
My MIL totally ignored my requests for wooden, creative, beautiful toys or experiences for our kids. she sent plastic, commercialized junk that the kids LOVED but then forgot about fairly quickly. I fretted every holiday, every time she visited with gifts (she lived far away) and every time she spoiled the heck out of my kids with her inconsiderate (towards me and my wishes) generosity (towards them) it drove me a little bit crazy.
My parents, on the other hand, quickly caught on that they had to be pretty careful in navigating my rules about gifts, so as not to annoy me. they started sending cash (or nothing at all, that happened a few times) and the whole gift-giving thing was kind of awkward with them. now they always only send cash, which is very practical, and the kids (8 and 10) are into it, but it isn't exactly thoughtful or memory-inducing...
MIL passed away a little over a year ago, and my children treasure every barbie, every spiderman, every little piece of plastic junk she ever gave them, because she gave it with so much love and affection -- she gave them things that she knew would light up their little faces, and as their grandma she had every right to do that. she fed them M&M's and root beer for snacks when we visited, and introduced my plain yogurt eating child to the glory of pink yogurt!!! she didn't get to see them very often, and I wish I had stayed out of it when she seized the opportunity to spoil them rotten!!
I don't know if you're blessed with an in-law as loving as my MIL was, but I miss her dearly, and would give anything for the kids to get to experience one more of her commercial crap shopping sprees -- yes, she was harming the environment, yes she was using commercialized crap to get closer to her grandkids, but it was really quite beautiful, once I was able to step back and remove my baggage from the equation.
just my .02...
My mother is HUGE on buying crap for my kids every time she is out. But is so excited to give it to them, and they just melt all over it. Not only does it make her life sweeter, but thiers too.