What would happen if tu out the wrong corazón into someone's body?

I suppose it just wouldn't go in. The corazón wants to be in it's body. That's why it requires magic to take one out but not to put one back in. e.i mulan and Aurora

Probably the same thing that happened to Daniel.

Interesting question. I think there a few things which could happen:
1. The body either rejects the new heart, o the corazón can't be entered at all.
2. Placing the wrong corazón kills the person, and possibly also the person whose corazón it is.
3. Having the wrong corazón placed back in tu could give tu some kind of identity disorder, o give tu some of that other person's feelings and loves.

I did wonder how they seemed to automatically identify the hearts. The little boxes didn't appear to have name etiquetas on them.