Why didn't YOU drive the 45 minutes to collect the presents / take the kids / do the stuff ?
Old age and driving are not good combinations - it takes more concentration and 45 mins for elderly drivers is a LONG time.
I take my grandmother the 15 minute trip to see her friend because she finds driving even that long too tiring
You are incredibly strange, self absorbed and well - rude. There is no other word. You are being rude.
Of COURSE they want to see the children open the presents. Of COURSE they want to be there; that's the WHOLE POINT - seeing their little glowing faces, the huge smiles, the hugs of appreciation, the kisses of thanks.
FC delivers presents that people buy. Sell your kids this story ASAP and you bypass the whole "but SANTA can get it" when actually you can't afford it or it's sold out for weeks on end before Christmas. Then of course your children will learn that people have worked long and hard to save their money to spend on presents - they will appreciate them more from people they know, IMO.
Sure, Santa can bring some - but not every single one, surely? How strange.
I think you need to ring the inlaws, tell them you're sorry for making such a big hoohar over nothing and book a weekend to visit them, or they visit you.
Don't be so self absorbed and ruin the relationship over a bloody christmas present, for goodness sake.
Do you realise how lucky you are to have grandparents for your children? Not only the people, but people willing to spend money on them and love them so much that they want to be with them to enjoy their gifts?