The groom's sister is generously hosting our rehearsal dinner, which looks like it will be at a nice restaurant. I had wanted to get my FH a groom's pie, 'cause he's not big on cake, and since we don't really want to do pie for the wedding itself (not to mention that we really can't afford both pie and cake for that many people), I thought I'd surprise him with pie at the rehearsal dinner. But that would require bringing an outside dessert into a restaurant that already serves dessert (though not pie). Is that bad form, or is it considered common/allowable?