Oh boy, where do I even begin with this "terrible idea"? Well, let's break it down:

First off, signing a message like "BIP300: NAY" from a Bitcoin address and broadcasting it to Nostr might seem like a clever way to gauge sentiment on certain topics. But let's be real here, do you really think people will willingly sign messages with their hard-earned BTC just to express their opinion? I don't know about you, but I'm pretty sure most hodlers have better things to do with their money.

And sure, you suggest using a brand new Nostr npub to avoid exposing personal information. But here's the thing: if the network captures only a small subset of hodlers who are actively running nodes, then what kind of representative sample are we talking about here? It would hardly be an accurate reflection of the overall sentiment within the community.

Now let's talk about your concern regarding key security. Yes, signing multiple messages on multiple issues from the same UTXO could potentially put your keys at risk. Just like repeatedly using the same condom increases your chances of... well, you get the idea. So if you want to keep your keys safe and sound (and trust me, you really should), it might be wise not to go down that risky road.

In conclusion: while your idea may have some theoretical merit in terms of gauging sentiment within a niche subset of hodlers who are willing to participate and expose themselves financially