Would the tipping be purchase-adjacent, like most tips are? Or would this be tipping for Genius Bar employees?

I would think customers would be more grateful for the latter, and more likely to want to tip them. But it would be weird to tip in such an environment, where one is not already making a payment. Also, it could lead to weird incentives and treatment, where big tippers are able to effectively cut the line for Genius Bar support.

Tipping? For doing their jobs? No.

You want a job that allows tips? Then take a job that allows tips.

If someone buys a $1500 Apple computer, are they expected to tip 20% - $300?? Craziness.

Tipping sucks. Businesses should be required to pay decent wages with no tipping allowed IMO.