[larrys]

"Why not? "

One thought that comes to mind is if you mention that you are also talking to "Sam " then "Bob" (who you are having a conversation with) can start to game Sam, or Sam can game Bob (when Bob mentions it to Sam later if they know each other).

So in terms of general business "loose lips sink ships" this is something to avoid.

So either party can play mind games with the other. And depending on the relationship of the two this could create a problem.

Other thing is that this gives the VC you are pitching a chance to drop things in your mind about the other VC that might affect your judgement. "Oh well he's a great guy but the one thing you need to consider is..."

My guess is PG might feel that the type of people in YC don't have enough experience to manage this situation properly so it's really similar to an attorney saying "don't say anything let me do the talking".