I am a very "do it myself since I know it will get done and I won't inconvenience anyone" type person. A friend volunteered to help me out with the wedding (practically begged) so I, knowing how well of a cook she is, asked if she'd be willing to do the cooking for the rehearsal dinner. She graciously accepted and we started some minor planning on it. 3 days later, she called me with some news. She was told that it is customary that either of the mother ofs plans the rehearsal dinner. So in fear of over stepping boundaries and to avoid stepping on toes/hurting feelings she's kind of backed out of it. She's a good friend and I want her to help. I've never heard this before. Is this customary??