I don't mind NDAs as long as they're reasonable and I get something out of signing them. In general I'd rather know things and not be able to talk about them than not know in the first place.

As FreeBSD security officer I handle 'do not disclose until date X' information on a regular basis.

Yes, unlike the OpenBSD guys, the FreeBSD guys don't mind being under NDA if it means they can release support for hardware sooner rather than later. Look at Sam Leffler and the ath driver (although he is no longer under NDA)