The Tuner

The tuning thing is starting to bug me.
There is a switch in the preamp to engage the tuner, but the bass needs to be plugged in for it to work.
The jack is a stereo unit and when you plug in the mono guitar cord into it, one wire is connected to ground which powers up the preamp.   The tuning switch on the preamp only disables the audio out to the amp while tuning - okay, makes sense, but why not enable the preamp a the same time?
Seems like a poor design.

Did some searching and found a number of people complain about it and the accepted work around is to carry around a cable or just the plug end for when you want to tune.