We just had something similar happening very recently.
I.e. Guests booked for a small family of 3 (5 months ago). So as usual: I thanked them for their booking and forwarded them my standard additional question list. Since then: Silence.
Which is not much of a problem to me, as that seems to be the case with quite some guests.
Their stay is not due for another month (and typically, when I still need additional details, I will start contacting the guests again some 2-3 weeks prior to their arrival. In order to obtain the last remaining pieces of information).
Recently I received a message from these guests (without me re-initiating the conversation), in which they informed me they were already very excited about their upcoming trip + the message: “My in-laws have decided to join us. We are now 5 in total. 4 adults and one child. I wanted to let you know in advance”.
I was a bit stunned over this, because they were not asking me, but just telling me (at least they were not lying). Neither did they send in a change to the reservation reflecting the change in the number of guests (We charge a € 10/night uplift for the 5th guest).
As already mentioned by others in this thread. There are pro’s and con’s to every approach.
In the past, any additional applicable uplift for extra persons, was clearly automatically shown in the listing. For about a year or so, this is no longer the case. In other words: How can a guest know, such an uplift might be applicable?
The only thing a guest may know is, they booked an accommodation that sleeps max 5. So there was still space for an additional 2 guests. Most likely it never occurred to them, that this might have financial consequences. Neither may they have thought about the rise in costs to the host for having to house more people. I.e. extra laundry, extra usage of supplies and utilities.
So basically we have the same dilemma as what this post is about.
And indeed: All of this is mainly driven by the rating system!
As it is very difficult to estimate the potential financial consequences, as a result of a single very bad revenge-review.
Therefore personally, I think it’s best to avoid as much as possible any discussion upfront. But I also do want to inform guests there is some financial impact. Whether you will charge them additionally or not.
I decided to tell them about the consequences. But at the same time, I also told them that we would not be charging the uplift (maybe in the false hope they will reward us somehow for this kind gesture 😞 ).
Obviously I used factual and kind words, because I did not want to come across as lecturing either.
And on top of that some people can get upset very easily over about anything. Especially when money is involved.
So for now, we leave the reservation as is (maybe not correct, but nevertheless). In the future we also have to deal with Tourist Tax (and in a lot of cases, this type of tax will be collected by Airbnb on behalf of the local authorities).
So in the future, the actual number of persons MUST be in the reservation (we have to report identity details of the guest to the authorities too).
I.e. the authorities can reconcile.
So I will indeed think about adding this information to the house-rules.
Doing guests a favor does certainly not assure a 5-star all over review (maybe they have already forgotten again about the kind gesture, by the time they are writing the review). And it is like, when you offer a discount. Even then (or maybe especially) guests may still criticize you in the review.