Right now if you add (and possibly change) artists birth/start/founding date, it displays just as "Begin date" on the created edit page. See example: http://musicbrainz.org/edit/15769297.
This kind of wording can great misunderstandings (and could result to incorrect no votes), as seen in the notes of that edit. For persons edits it gives an impression, that in case of a performance name someone is trying to add a invalid begin date, when it's actually a valid birth date.
Wording should be based on the artist type. For persons it should be "Birth date", others might be OK with "Begin date".

This might apply to "End date" as well.