Let me explain as this sounds weird. So my wife and I are foster parents, and one of the very few things you do differently for foster children than you do your bio-children is a kind of screening of their toys (and other things but lets focus on toys).
For example if you have a child in your care that is, due to abuse, sensitive to loud sounds, you avoid loud toys. If you have a child that is, due to past occurrences, prone to play with dolls in a sexual manner, you avoid dolls. Some of the things you "filter out" may seem odd from an outside perspective.
Another great example are toys that encourage expression, creativity, and interaction are favored over toys that are "one player" in many contexts as it gives foster parents a way to interact on their level. At the same time, toys that are for group play may not be the right choice for children that are currently having behavioral problems in groups.
Lastly, at least my wife and I take co-parenting very seriously, and use every opportunity to involve the bio-parents in the decision process. Sometimes, for one reason or another, they request we avoid certain toys. When it seems reasonable, we try very hard to comply. When it's not reasonable we try to be flexible and comply anyway, but the concept of reasonable is objective, and sometimes we're not able to. For example, we provide nook tables to kids of all ages. If the bio-parents don't like that (none have had an issue so far) then I don't know what we would do, as it's the primary way the children would read, watch "TV", and many other things.
At the same time if the bio parents recommend certain toys, as long as we feel they're safe, then we try to get them. This has never been a problem for us. No one has ever tried to recommend we get a 4 year old a chain saw. But it could be a problem, for example if a parent recommended the entire Disney VHS collection. First because we don't think kids should watch that much TV, second because we don't have a VCR (or anything to hook one up to).
So toy choices (in this example) can seem unusual.
How do you get others to accept your rules for toy choices?
We have a large problem with "others" getting what they think will be fun. For example a neighbor getting a toy for our foster child that would normally be perfectly fine, but for this case, it's not ok.
This usually falls into two categories.
Ignorance the neighbor just doesn't know that something as "normal" as a play dough play set is a trigger for this child.
Being Ignored usually not neighbors and friends but "grandparents", just going - "It's ok, you liked playing with it when you were a kid" (or similar). And just ignoring our rules as unimportant or wrong.
So, back to the question, how do you enforce your toy choices, when other people may not understand or respect the boundaries. And failing that, how do you "take away" a gift because it is a trigger, even though the child may not understand that?