A few years back, I was interviewing at a then "hot" startup. At the end of the process, the CTO calls and says they'd like to extend an offer. I was expecting him to walk me through the offer details, when he goes "well, are you going to take it?" I asked about getting some specifics (cash comp, equity, etc.) and he explains that they ask candidates to commit before sharing any details.
I told him that didn't seem like such a great idea, and he assured me that comp wouldn't be an issue, and that they do this to avoid hiring mercenaries. I passed and never looked back.