Here's a dirty little secret: Most 'confidential' or 'close to the vest' information we get comes from people talking and answering questions they probably shouldn't answer. I'm not sure why this happens over and over but they do.
So, make a little card for yourself and carry this around with you when you are on the money hunt. Since nobody wants to take my advice to simply not answer these questions, I've provided handy answers so you can feel good about saying something.
1. Who else are you speaking to? [Answer: The usual suspects.]
2. What pre-money value did you have in mind? [We are looking for a deal that provides great returns for all of us.]
3. Can we speak to a few of your customers so we can better understand the value proposition? [No. Customer calls are post term sheet due diligence]
Really. Don't answer these and if you must, see above.