Etiquette Question re: cloth diapers/shower

mmm50

My mom and MIL have offered to throw DH and I one big shower with both sides of the family.  (We're still not sure if my mom and MIL will "host" or if my sisters and DH's sister will be the "hosts" and mom and MIL will foot the bill because my sisters are in college and middle school and DH's sister doesn't have money--- but that's up to them to decide.)  My mom asked for my input the other day on themes, invites, guests other than family, etc.  We plan to cloth diaper (and are the first people I know of in our family to do so) so my mom mentioned that maybe we should put that on the invites.

 My question is:  should we put that info in a note on our registry (as in "It's a BOY!  p.s. we're cloth diapering--- obviously worded much better than that)?   should it go on the invite inserts (the little business-card sized card that often comes with invites containing the registry info)?  leave it out completely and up to word-of-mouth?  I am incredibly thankful for anything we may get at a shower, but would like to avoid having a ton of disposables to return or donate.  I also feel like some of my family would complain that "someone should have told them" if they bought disposables without knowing that we are CD-ing.  

 My instinct is just to put a note on the registry-- and register for CD supplies, and not do the registry info cards with the invite.  Do you think that is the correct approach??