As Sasless says, Jackstall does not 'lock up' the controls, the aerodynamic backloads (particularly on the retreating side with the highest AoA) overcome the power of the servo jacks and force them to the bottom of their travel.
The resulting pitch up and roll right is identical to retreating blade stall.
Recovery is to reduce the severity of the manoeuvre, either by reducing collective pitch, relaxing back pressure on the cyclic or both, depending on the flight regime. If the controls were locked up, recovery would be impossible. Turning off the hydraulics will not help, even a little bit.
If the controls 'lock up' you have a different problem or you have misinterpreted what is happening.
As for wazzing and zooming with skiers on board - don't push it to the limits and don't think that giving them a bit of a thrill entitles you to exceed what you would do with your wife and kids on board.