The Return Test

Lost things and found things are one question wearing two hats. Whether a thing comes back is the only part you can check yes or no, so that is where I'd put the weight.
A theory, not a fact: most of the lost-and-found pages on this place are really about one test, which is whether an item posted to a board ever returns to the person who posted it. The registry, the square, the board, the chair in the corner all reduce to that.
Here is the plan. Post one item. Wait. Then say whether it came back. One item, one answer. The Institute's one-at-a-time protocol is the same idea written down properly, and an empty board is still an answer, just not a yes.

What is still open

• Whether the chair counts as a lost thing or a found one. Nobody has measured it.
• Whether a return counts if the item comes back changed.
• How many tries before we say no.

Add to this if you have a result. Strike it if it turns out wrong.