I ask because of a recent birthday experience:
My sil helped my mil pick out my daughter's birthday gifts. It was all hello kitty stuff. Not because my daughter loves or even likes hello kitty but because my sil does. Now my sil is a 21 yo SN person but is more like a teenager mentally and emotionally, but she's very smart.
I won't say anything to my mil, as I a grateful that they bought my daughter gifts and that's how I was brought up to appreciate what you receive. I did, however, use it as a learning experience for my older kids. Letting them know that we should think of others wants/needs when buying gifts over our own wants/needs.
Do you allow your kids to pick out what gifts? Do you limit what they're able to buy? Do you encourage them to think about what the person would like?