This is a MUST now that Pro Tools is more mobile. Ableton has it and Logic both have it.
It is a necessity for easily auditioning Software Instruments or even laying down ideas on the go - ie on a laptop. Why this hasn't been implemented into Pro Tools yet is absolutely mind blowing.
Solution: It is very simple. Just like there is a keyboard focus button which activates all the shortcuts there could be a "Midi Keyboard" button which turns the feature on and off. Caps lock does nothing in PT at the moment, that would be ideal.