Anti-shake Angst

[Ptax]

On my Pentax K10, the "On/Off" switch for the Anti-shake feature is on the back of the camera. I do a lot of hiking and carry my camera out and ready for those unplanned wildlife shots. I have found several times the switch has been inadvertently moved to the "Off" position. Short of a piece of black electrician's tape, I cannot think of a solution. Any other ideas?

Also, on what occasions would I want to consider NOT using the anti-shake feature?

[EOSThree]

Don't know what to tell you about the switch.
The times not to use IS is on a tripod or some other form of support.