How do GA glass cockpit attitude indicators handle aerobatics?
Caging was required when Gyros were mechanical masses actually spinning at many rpms in their cases. That mass resisted rotational motion and produced a resistance force that was measured and translated into useful info like pitch and roll. That spinning mass carried much momentum in the form of its mass times its rotational velocity. And too much sudden motion and the resistive force/momentum could  cause mechanical stress to the unit and/or cause the instrument to tumble. So it became helpful to cage a gyro before acrobatics to keep the thing from busting or wearing out prematurely.

In modern glass cockpits like the G1000, there are no mechanical gyros with high mass parts (excepting a standby instrument independent of the glass system, which may need caging if it's a mech type). The gyros that are used for a G1000 system are called MEMS (micro electro mechanical system) gyros which do not have a spinning mass. They have tiny metal discs that merely vibrate. When they are rotated (by pitching or rolling), the vibration dynamics change a little bit and a capacitive reactance apparatus measures this change which is directly proportional to the rate of rotation. 

The MEMS gyros can take aerobatics without enduring any mechanical stress what so ever so there is no need to cage them.

The system does however, loose accuracy. The rotation rates offered by the MEMS gyros are prone to micro errors and these errors add up over time. The more rotations, the sooner the sum of all errors becomes significant. There is a software algorithm that re-aligns the system periodically and basically erases the errors (it kind of reminds the system which way is up). The algorithm uses accelerometers (like the one in your phone) to sense stable, un-accelerated motion, and at that time, the accelerators can sense gravity which points straight down. When this occurs, pitch and roll angles are keyed off the accelerometers and the rotation rates are reset to zero and the system is ready to start keying off the gyros again and adding up errors. In normal flight like touch and goes or cross country flight, there are lots of opportunity to reset the errors. In aerobatic flight there are fewer opportunities but once the aircraft eventually returns to level flight for some period of time, it will reset itself. Whether or not the error can be significant enough to be noticed by the pilot, I don't know... probably depend on many factors, but I'd probably be intimate with a sic sack by then.