Private Message on Catalog (Coin not in your collection)

I came across one of this situations were there is a coin that I am very interested in, the coin is not easily available in the market but every 2 years or so, one pop in auction sites.

Will be possible to add a private message to a coin that its not in my collection for future reference e.g. Last prices the coin was auctioned?

Once you click to edit the coin immediately add 1 to your collection, but if you add comments and remove the number once you save the coin it gives error.

I believe there is a good opportunity to add comments for specific coins in our wanted list, as there is a way to "I wish to get this coin"

The idea is already tracked here: https://en.numista.com/forum/topic67836.html