I think you need to have a chair on the crate. People can get on top of the crate by sitting in the chair. Once they are sitting down, you can remove it, and they are left on top of the crate. I'm almost 100% sure that's the only way to do it. Correct me if I'm wrong.
Yes I know that trick but I was in Tink something room on the dis coffin teleporter network and I was able to stand on her crates. Looks like she put something in them so I could. I have a great fun idea if I can get it to work. Thanks for responding