Demand to see how the breeder/keeper keeps their snakes. No
Ask to see their parents and how they have been keept, yes - but why would that offend? It wouldn't offend but it means access to my collection and that is No from me.
What I was meaning to say was, asking to see the parents is a reasonable question. Asking to see their other collection of snakes eg GTP, albinos etc isn't.
Of course if I turned up at your doorstep interesting in purchasing a python and you asked me "show me your cash" I would be offended and it would be wondering why. To show the breeder that you're serious, well prepared buyer, even if you decide not to buy in the end.
Scenario: First time snake owner. researches the python they are interested in purchasing. they will not know how much security is actually needed. a first time snake owner asking to see your animals wouldn't know right from wrong. I never would thought it would offend you to see your animals. now of course I do with experience and i've learnt more about reptiles/hobbies etc
edit: and if they seller refuses, I respect that, i'm not going to kick up a storm, I understand the security involved now and why they wouldn't like me to view it. after all I am a stranger to them.
I have to say, I can't even imagine a stranger walking through my place, looking at my set up and then walking out to think about it. Honestly, it would freak me out and I would probably report that person to the Police in case something goes wrong at later date. I am not a shop or a factory where the public can brows through, no matter how honest their intentions are.
I am weird?