This is a cool idea. I imagine that as they change their hiding places and they become more commonly found, they would start exporting these items all over since they have lost their purpose. Might be why the PCs found it and could be a little known specialty store that offers these kind of items.
I like the immediate usability of the items and the amount of them that could be available. Assassin plots come to mind, PCs needing to get some weapons in somewhere, PCs get caught unaware by one.
I almost wished it was a scroll to see more ideas. None come to mind from me right now but the opportunities are really endless. Go to Comment
Sounds reasonable and you do a good write-up. Once these things got found out, of course everyone would know to search there and they'd have to scrap the idea and make a whole new one... but while it lasted it would be good. Go to Comment