Yes, @Gillian19 that is true. Unfortunately, it seems that Airbnb doesn't always update their call centre staff on new policy changes very quickly or at all.
When this stupid 88% Acceptance Rate criteria was brought in, I got quite worried, because like @Emiel1 I started getting the exclamation marks on my dashboard that one of my listings wasn't meeting basic requirements. How could that be? I was a Superhost!
Anyway, it turns out that:
1. Most of the reps I talked to initially had no knowledge of the 88% acceptance rate criteria and kept telling me that it doesn't matter how many times I declined, I would not be penalised. Others told me that it was probably a technical error and that they would look into it and get back to me but never did.
2. Slowly, the reps started becoming aware of the criteria. I was told by one that I would not be delisted, but I should accept ALL requests going forward. The rest told me it didn't matter, that I would not be delisted and one told me that it was better to decline than risk my response rate going down.
3. This criteria is not part of the Superhost requirement, so you can get warning messages about it at the same time as glowing messages telling you what a wonderful host you are. The acceptance rate for one of my listings was below 88% for many months and I kept Superhost status throughout.
4. If even a host whose rate drops to 17% for one of her listings still doesn't have it delisted and keeps her Superhost status, then clearly it is just an empty threat to try to coax (or bully) hosts into accepting everyone! Perhaps that will change, but for now, I don't think it's a real threat.
My way around this, which usually works, but not always, is to try to convince the guest to withdraw the request. If the request is completely unsuitable, e.g. asking to accommodate more people than you maximum, bring infants or children when you don't accept them, demanding a discount etc etc. and the guest is not withdrawing the request or responding, you can call Airbnb and ask them to cancel the request.
I have only done this a couple of times because it's all very time consuming, but it worked. Otherwise, just hit decline before the 24 hours is up. It's not ideal as it can affect your search ranking, but it's better than having to host a nightmare guest who is going to be dissatisfied and leave you a bad review/ratings as that will probably affect your search rankings more and be stressful all round.