I've never had a seller make that proposal. I think I would be amenable.

It's considerably easier and more common for lack of skill to damage a bike than a car. Consequently in motorcycle sales, ads will often include something to the effect of "test ride only with money in hand and MC license". I've managed to test ride three bikes without meeting the "money in hand" part, and ended up buying two of those. In one case, it was a pawn shop with a Buell that seemed to be getting disillusioned with that particular piece of merchandise. The next time I told the seller approximately how much money I had in the bank at the time and only rode the bike around a parking lot. The third time I just informed the seller that I was looking to replace my previous bike and I got offered a test ride. I showed up in Navy PT gear. Seller was a Navy brat. Having full gear (full face helmet, MC jacket, gloves, and boots) in the trunk probably helped. Showing up in a Benz probably didn't hurt either, and neither did the fact that the bike had already been down more times than Linda Lovelace and was priced to move.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.