Bubble level as cheap insurance for inadvertant VFR into IMC

[Sonex1517]

I put a GRT Mini in my all steam gauge panel specifically to address this.

I also built and installed a Lift Reserve Indicator.

Both are, in my opinion, great safety enhancements.

[rizzz]

I just read the Error Chain article by Michael Robinson in the October 2015 Kitplanes magazine "Aeronautical decision making—it seemed like a good idea at the time"

In it he shares his near death experience when he has no reference to the horizon. Wouldn't a simple bubble level that costs a few bucks and weighs less than half an ounce be a good thing to have on the dashboard? Would the vibrations make it unusable?

As others have mentioned, this device would just be a much too sensitive slip indicator. won't tell you anything about roll (or pitch).
You could still find yourself in a coordinated spiral dive in the clouds with the bubble perfectly centered, you'd be in for one hell of a surprise coming out at the bottom. (I know of one glider pilot this has happened to BTW, when she eventually came out at the bottom she ended up pulling so hard to try and recover, she ripped the wings off the glider, sadly that was it).