I didn't think I was going to be having a shower, but when a few friends found out I wasn't they offered and I am so grateful I gave them my small list and then several people asked if I was having a shower and asked to be invited if I was, so I added them to the list. Those are the people that haven't rsvped and my shower is next weekend. I know they still have time even though the rsvp date has passed, but why would you ask to be sent an invite if you can't even rsvp? I know it might be a date conflict for some people, but just say no and don't make the hosts wonder...
Even one of my coworkers who just had a baby and shower and complained about our mutual coworkers not rsvping to hers didn't respond either. I know she has a 6 month old, but she just went through all of this!