Exactly.
A little different from fostering, but we are in a situation of having just taken guardianship of our 11 year old great-nephew. When we took guardianship, we fully expected to take on the entirety of his care including vacations, Christmas gifts, everyday needs, extracurricular activities, etc.
Then we found out that his mother and maternal family (and parts of his paternal side as well) consider the definition of "raising" a child gifting him with everything under the sun with expensive gifts and cash, but letting everyone else actually raise him. We have had him since August and he gets a card with $100 cash every month from some aunt,
Amazon deliveries every few weeks with toys, video games, pricey gym shoes and Halloween costume pieces, and has come home from his mother's house on the weekends with a new phone and bluetooth earbuds, among other things. He came to us with a minimal amount of clothing so I went out and bought enough to get him through at least a week of laundry, then he tells he later that he has at least 3x as many clothes at his moms house (it came up when I told him to pack a bag for the weekend the first time he went there for the weekend). My fault, I guess, for not clarifying it with the mom, but I would have thought she would have sent most everything he has since he is with us 5-6 days and with her 1-2 day a week, if that!
We actually had to tell his mother to tell everyone to stop sending stuff to our house and send it to her instead because my own 11 year old who has been a GREAT sport about the whole thing, is now sharing his entire life (bedroom, belongings, school, classes, friends, etc) with nephew and is getting discouraged at his own life turned upside down while his cousin is getting the best of all worlds (in DS11's eyes, at least. We understand the reality)
Anyway, nephew told us that he has 4-5 relatives that he gives a Christmas List to, who usually buy everything he asks for (this year he is asking for a laptop and hoverboard, among other things). So, DH and I revised our plans to be "fair" and make sure he is on par with what we get our kids, down to 2 gifts - one is an early gift of theater tickets to see White Christmas on Nov 28th in downtown Chicago (my kids LOVE that movie, so we are surprising them with tickets on T-giving, and Nephew will be with us since it's a weeknight) and dinner before the show at Sugar Factory. His 2nd gift will be a college-themed shirt/sweatshirt for the college he likes. He will be with his mother for Christmas so we will give him his gift before he leaves for her house Christmas Weekend.
My out of state family does a pick-a-name for the grandkids, so each kid gets one gift at our annual Christmas party. Nephew is not included in that as he will not be there for the party (he will be at his mom's) and he has several aunts and uncles in his family who get him gifts (see above). If this wasn't the case, and he was coming to the party, he would be included in the gifts. I don't think my mother will be getting him anything because she has never met him. Nephew's grandparents do not get my kids anything - his maternal grandfather is my kids' uncle and he has never bought my kids a gift for any occassion.
If my nephew didn't have the steady stream of gifts from his family, we would make sure he had an appropriate ratio of gifts to what we give our kids. I feel it comes with the responsibility and honor of taking care of a child. IN this case, though, nephew is getting more in both qty and value than my three put together! I cannot justify splitting my gift budget by 4 instead of 3 when one of them will get way more than my kids will ever have.