We caught a soft opening of the Fantasy Land expansion in 2012 and it was awesome. We got to see Enchanted Tales with Belle (it was MUCH longer than the current version), rode the Little Mermaid ride, and they were allowing people into Be Our Guest without ADRs, and Gaston s Tavern was open, too.
Disney had a CM at the entrance (which was blocked off) and we walked up and asked if they were letting people in, she said something like "not everyone but we're letting YOU in -- enjoy!" and moved the rope for us.
I had read the soft opening was For Annual Pass holders only, so it was quite a surprise!