There's another solution to the whole stage tech issue: software.
It's not at all uncommon for bands to use click tracks synced to external effects such as lighting and pyrotechnics. The triggers are pre-programmed. A midi controller could be interfaced with the computer running the click track and triggers built into it at certain points in the song. The midi controller could then switch on and off guitar effects as necessary. Malmsteen uses a foot-activated midi controller for his guitar effects, but the midi triggers could come from the computer, too.
In this way, there really is no need for stage techs to turn anything on or off. Once the song starts, all the effects are triggered at pre-programmed points.
It's not at all uncommon for bands to use click tracks synced to external effects such as lighting and pyrotechnics. The triggers are pre-programmed. A midi controller could be interfaced with the computer running the click track and triggers built into it at certain points in the song. The midi controller could then switch on and off guitar effects as necessary. Malmsteen uses a foot-activated midi controller for his guitar effects, but the midi triggers could come from the computer, too.
In this way, there really is no need for stage techs to turn anything on or off. Once the song starts, all the effects are triggered at pre-programmed points.