Pretty well covered so far, but I'll add my $0.02 anyway, starting with a quote from another thread:
Every action we as tapers take (or fail to take) as individuals reflects on the broader taper community. Likewise, traders' actions reflect on the traders and the tapers.
It's not just about me, or you, the night we tape. It's also about musicians, venue management, security, band management, musicians' labels, even fans, and their individual and collective perceptions of tapers, what we do, how we do it, why we do it. A single, simple wrong step may have broad-reaching repercussions. Stories abound of a musician or management or venue getting pissed off at a taper, or group of tapers, and shutting taping down temporarily or permanently, or causing conflict and tension, bad blood between fans and tapers, tapers and musicians, tapers and management, tapers and venues, etc. Is sharing a recording against the musician's or management's decision really worth risking the potential down side?
IMO, disrespecting the wishes of the musicians, venues, security, management, etc. isn't worth the downside repercussions. I think this holds true
especially for situations in which the musician or management specifically requests a performance not be shared. Sharing anyway, even among a "trusted few", simply doesn't work - the recording gets out eventually one way or the other, and if the musician gets word of it...we don't know what repercussions might be in store. Maybe none. But possibly significantly negative ones, too. Multiple references on TS reflect this experience: share a recording even once, and you lose control. Please don't put someone else - trader, fellow fan, even another taper - in a position to jeopardize your personal or our community's relationships the musicians, etc. or negatively influence their perceptions of us and what we do.
[/soapbox]