Wordbiker

Customer riding bike too large for them with not enough seatpost exposed to clamp + frozen seatpost = hanging by the seat for small repairs.

While I also agree it is not a good practice to do this, just yesterday I had one heck of a time with a customer's seatpost due to them installing it sans any grease or assembly lube. The frame was a swoopy carbon Orbea...no chance of clamping the frame. Had to pull the post with much effort, clean both the post and the frame and reinstall with carbon prep....all just to clamp the bike and perform a task unrelated to the seatpost. That's a bit of labor and materials I can't charge for, so I can understand other busier mechanics using the shortcut.

BTW, the other work I was performing involved fixing their home BB installation w/o a torque wrench.