Would you pay to listen?

Yes, I would pay and have done so in the past. There's a firm in my area that does consulting for designers and manufacturers of audio gear. I'm not one of those, just a listener, but I asked and they had some free time. Took some discs and found out what everything on them sounded like. Bonus, got chat time with the consultant. Was more than 20 bucks an hour though.

No. WHY?... I have listened to $100k systems and maybe more. They sound good to excellent. Some I thought they were just putting expensive stuff together in a room for that WOW factor. (A lot of sizzle but no steak!) It is not even remotely necessary to spend that amount unless your space is very very large and you live next to the airport or subway:)

Will they offer a refund if you are not impressed?

If your space is like most 10-12'x 12-18' up to 30' you can put together a musical, dynamic, well matched system for much less including room treatments if needed.

Almost any knowledgeable audio dealer will have the ability and the means to help you assemble a system for less than $25K that will rival even the most expensive. The retail price of audio products is a poor indicator of sound quality or synergy. As you know 95% is marketing bable and fancy photos. There is very little to no evidence or science to support their claims or prices. i.e.(the face plate and casework can exceed the price of all internal componets on many high $$$ pieces).

You can listen to excellent sounding systems all day long in most every mid size to large city or suburb for free. Use the $20 to buy more music or pay for gas and travel to a dealer out of your area and hear equipment that is new to you. Develop a relationship with an audio dealer near or far that you trust and work with them to achieve your listening goals.

One hour with one system? No (unless the drinks were Krug Clos d'Ambonnay in which case I'd go listen to a Bose system).
Who is going to decide which is the "best matched system" anyway? I have heard dozens of representatives at shows make that claim - at both price levels - some of which were downright awful (matter of fact, I can think of three who should have paid me for the hazard I had been exposed to).
To get one thing out of the way, then, why will I pay entrance fee for a show such as the Munich High End (€ 10/day) even if I have to accept far from ideal room conditions, struggle with the crowd in the hyped rooms and deal with disturbing ambient noise? I'll pay for an entire day of comparisons I can otherwise not make (and gain valuable information who's making the best out of it under such conditions).