I read instructions in a drone magazine on how to roll and flip a quadcopter. Can my Mavic do this, and is it a good idea?

Nop, cannot. Try DIY. DJI has SNAIL propulsion system. You may try some opensource fc.

Sure, the Mavic can roll and flip.  The problem is you have no control over when it's going to do so, and it will usually result in a wrecked drone.  Here's a thread from last month in case you want an idea or two for things to try.

Trying anything like you read in that drone magazine will not do anything interesting on the Mavic, because it will remain upright even if it has to ignore your commands in order to do so.

Nope, it can't roll and flip. Don't try this, it may result in a crash.

I would not advice so.
There are many 'stunt' drones that can

I've only seen the small racing drones do it in videos

I managed to do a flip (WITH THE DJI M600) via the DJI onboard SDK, although i needed to go to 25 meters, and whould use up all the height.
It was only in the simulator tho xP

No, i wouldn't try to do a flip, one is because it is quite an expensive drone and there is a pretty big chance of crashing it, the other is that if you are looking for a drone to do tricks with, i'd buy a cheaper drone or one hat is specialised in these 'tricks'. The mavics are more for shooting footage rather than doing tricks.

The new CAPTCHA crap is the last straw.
Im tired of DJIs crap and am removing my posts and will be on my way.