I think there's also something to be said about expectations. I do two Christmas programs with the kids, Christmas Shoeboxes (with Samaritan's Purse) and Toys for Tots. One of the things I like about Toys for Tots is that they are partnered with Toys 'r' Us, so you can pick out a gift and drop it off in the box by the door. It's really convenient, versus trying to find a dropoff location and get there in time. So I take my girls to the store, tell them their budget, and tell them to pick out something *they'd* like to get (they know what it's for). Then we buy it, and drop it off in the box as we leave the store. With the shoeboxes, you just stack them in a pile at the church. However, that's what I came in expecting, so it doesn't bother me that there's no special dropoff moment for my kids to experience.
But especially if you'd experienced what the PP's son had, I can really see why just dropping it off would be a bit of a downer, and then to be treated like a nuisance on top of that! That's really obnoxious of them. I'd definitely have called the office or the corporate headquarters and talked to them about it. I mean, I can see their concern, with lots of exposed children's toys around, that children of visitors might try to play with the toys and mess them up. Maybe they'd even had special snowflake children do it in the past. But that doesn't mean they should jump on all children, or do it in a way that makes the children feel unwelcome.
Even saying, "Welcome, everybody! Thanks for bringing presents! Now, kids, I know there are lots of great toys everywhere, but please don't touch, because we want them to stay in perfect condition for the children who need them," might come across as a little patronizing but probably wouldn't have made the kids feel as unwanted.