@Debra300 I did a lot of thinking and decided against it. Here are my thoughts:
1. I have a big house that is usually booked by a big group. They plan ahead. My chance of rebooking 5 weeks before the trip is the same as a week before the trip (slim), at full price anyway. I would rather get my half guaranteed and can always rebook for half the price.
2. If a group wants to cancel and they nothing back as far out as a month out, they will drive me nuts begging for a refund (with airbnb's help, I am sure)
3. I want people to book when they made up their mind. No place holders. Because I cater to groups and do not charge per person, they should still be able to make a booking decision even if a few people are undecided. I do not want someone booking it just in case or worse, shopping around as it gets closer to the time.
4. The quality of guests who book at the last minute is worse. I want planners who are coming for weddings, etc
I am not a marketer nor a professional operator so I could be completely off here.