What you’ve described is a model who is accepting a not-ideal arrangement out of fear for ending up in an even more dire financial situation.
It suggests the model accepts this type of non-tipping visit not because she prefers it, but because she’s afraid of the alternative. The member is implying leverage over her, by letting her assume “if I expect tips every show, he might completely take away his business.”
You may be correct that this happens, but it still feels exploitative. You suspect the model could be a little desperate (no other visitors in the room, seems ok with not getting tipped every visit, etc). And if you suspect this is her reasoning, it’s within your power (not you specifically, but the member) to reassure her otherwise. Especially if you’re “friends.”
If you don’t take it upon yourself to offer that olive branch, you’re letting her assume there’s a risk in expecting tips when it’s a slow day, and in a way, you’re benefiting from that assumed risk.
And to Mysterical - in my opinion, falling back on “well, her room, her rules, and she said she likes when I visit on slow days” also sort of construes your visits as a favor to the model. And I’m not going to dispute that she enjoys spending time with you. But my point is, unless you’re 100% doing it as a favor to her, and you get nothing at all out of it, then you should consider the value (monetary) of whatever you get from those visits.