If someone shows you might learn they are not a guest, but having the 'correct' "La" letters does not mean they are a guest.

The advantage is a doorman can have a tiny list to direct people inside, the downside is it's poor validation and does not scale very far.

PS: You can obviously add more letters, but the same problem happens if two people have the same names.

So, if you know that Peter is wearing a green shirt today, then you can rule out his being there if the guard says nobody wearing a green shirt has arrived.

Is this a rigorous model? No. It is just an easy mental model for me to conceptualize this.

If you really want to use a range of questions then police codes is a good proxy. The guard may say we have people in the drunk tank, but not anything else.

Again, not a rigorous explanation. Just an easy one. For the advanced algo, I typically word it as imagine if the front desk had a notesheet that they would tick next to "person carrying a backpack" and/or "female" and/or "male" and then I could run my candidate through the questions related to them and see if they all have non-zero quantities of people.

But, again, just a mental way of thinking about this in analogy. If you aren't the kind that needs/wants analogies, this is worthless. On that I fully agree.

Not sure a bloom filter needs an analogy but there you go.

Now, if you are saying the guard internalizes this with "has someone with that hair color entered? What about of that height? With that facial hair? etc. Then, yes, this is the same.

Analogies can almost always help, for the class of people that are helped by analogies. :)