It really depends. Who owns the bike? The shop? in that case, no. Him, in that case yes. If I do ride a bike, I'll take it *really* easy. Unless I know the person well and know they are happy with me riding it. Then I might ride at normal speed. Still wont go anywhere near pushing it though.....
If I've been asked to test out a bike for someone, that is a different story. I'll intentionally lock brakes and such like, stoppie, run it to redline. For the purposes of testing you understand....
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