This is a case of what you are suggesting being completely reasonable and making total sense. Despite that, my inclination is to not do it. Nanny posts have been an issue for us going back to the original DCUM Mailing List before we even had website forums. Nanny posts grew to be more than 25% of the posts on the list and started drowning out all other topics. When we decided to keep nanny post off the mailing list, we had a lot of resistance from some subscribers. Even with the forums and even when we had a nanny forum as part of the main site, we've always had problems with nanny posts. Not to be overly dramatic, but they seem to spread like cancer. If you allow one, you encourage more and pretty soon they are out of control.
I recognize that posters might not get the desired response if they post in the Nanny Forums section. On the other hand, General Parenting is already the most heavily used forum. So, nanny posts in that forum would crowd out more appropriate questions. I would rather apologetically explain to those who want to post about nanny issues that DCUM cannot help them then to give the same message to those who want to post about non-nanny parenting issues. The only alternative would be a separate forum in the main section for nanny topics, but I don't want to take that step for a number of reasons.
Nanny posts do generally get a free few hours before I notice them. It's the few days that you suggest, but it's better than nothing. But, generally, I feel I need to take a pretty hard line about nanny posts. Right now I need to figure out what to do about this one:
http://www.dcurbanmom.com/jforum/posts/list/421413.page#5921653
(which will probably be deleted before you see it).