"Excuse me, is there a taxi stand here?"
Great question, and I've been trying to think of a clean explanation and I'm coming up blank. For every example of NOT needing 在 I can think of counter-examples where you MUST use it under similar conditions. Best I can come up with is that sentence beginning with 这里 or 那里 typically don't need 在. Here's what I mean: 那里的天气很好 vs 天气在那里很好.
I'm not a native, but I lived in China for more than a decade and am a fairly fluent speaker. I'd be open to correction on this from a native speaker.
Speculating here, but to me it makes sense this way:
出租车站在这里 implies a specific taxi stand. "Is the taxi stand here" 这里有出租车站 the object is 'here' as in "does here have a taxi stand" or "Is there a taxi stand here"
The practical difference comes out to be an infinitive vs definitive taxi stand in a language that otherwise lacks a distinction between infinitive and definitive ( THE taxi stand vs A taxi stand).
I'm not native, so don't take me too seriously.
在 + Location can be used to create a prepositional phrase that indicates the location where a verb takes place. Subject + prepositional phrase + verb + object.
The verb 有 is used to indicate possession (person有object) or existence (location有object). In this sentence, 这里 is the subject of the verb, so using 在 to turn it into a prepositional phrase is unnecessary.