This is in AIBU but is actually more of a WWYD (or say).
My in-laws (PIL and SIL) always ask us to allocate them something to buy for DC from their Christmas list. They have not once ever gone into a shop and picked something out, even when told things like - they like lego or a book on a subject. What they want is for me to give them something to buy off my Christmas list for them.
My DC do not get loads of gifts. I just wrapped them all and they have 10 each. That is not 10 big things. It is one main, 3 or 4 smaller things (£15-20 each maybe) and then tiny things like a bar of chocolate, pens, new pencil sharpeners. I spend a lot of time on each of their bigger presents. I start looking in Sept and am very choosy in what I buy. I come on here a lot and ask questions, follow threads and research and read reviews, then scout around for the best price. In the past I have given them something off the list and then my DC are delighted to get it - off them 
I have never had to ask any of my relatives to pick something off their list for me to buy. I am quite capable of asking a general question about what they are into, then selecting a gift. There isn't anything stopping them doing this themselves. In the past when they have asked me what to buy them I have tried to keep it to things like pyjamas, slippers or clothing but they say that is not a proper gift.
I am getting nervous that they are going to be here on Christmas Day and then pull me up on what my DC have opened. They have some really nice things to open which have clearly had a lot of thought put into them. I am pretty sure they are going to ask why I didn't allocate some of them to be given via GP's and SIL. Told them that they were saving up to buy a specific thing and to give them vouchers for the shop.
I know this sounds really trivial but it is annoying. AIBU and/ or what do I say if they put me on the spot.