I have placed a reverb send on a vocal track with reverb buss going to the master. I also have a piano track (no send) sent to the master.  When I solo the piano track I still hear the vocal track when the vocal send is set pre send. Is that right? I thought the reverb buss would only effect the vocal either pre or post.

The "pre" setting means "pre fader", not "pre send". So that means the send is not influenced by the level of the track. So in this case, soloing the piano has silenced the vocal track, but not the signal being sent from it. If you set it to "post fader", that will silence the send when the track is silenced. However, the send level will now be linked to the level of the track.
 
This is actually a more typical scenario, as the level of your reverb send will maintain the same relationship with the dry signal when you vary the dry signal's level.

Thanks John.