The M20K POH specifically states “Fuel Boost Pump – OFF” in the “Takeoff” section (pg. 4-10) as well as the “Before Landing” one (pg. 4-14). I don’t recall it being “ON” anywhere earlier in the normal procedures. The only reason to turn it on is during high ambient temperatures, to overcome vapor locks, and in emergency situations (power loss, etc).
Some checklists say to start on less-full tank, taxi on it, change to fullest tank for engine checks and take-off, with electric pump on for take-off after the checks.
Regardless I start, taxi, and take off on the same tank. At a safe height I change.
The DR1050 always takes off on front tank, which has some gravity feed if not in a climb.
On a number of occasions I’ve had a problem on changing tanks. Not detected until I switched the electric pump off. Causes:- leaks in fuel system, and once a partially blocked finger filter in the rear tank.
Some checklists say to start on less-full tank, taxi on it, change to fullest tank for engine checks and take-off, with electric pump on for take-off after the checks.
That’s exactly what the TB20 has, and I thought it was standard for low wing. The reason is simple: verify both paths comprising the fuel system, before takeoff.
Regardless I start, taxi, and take off on the same tank. At a safe height I change.
I would do that only if for some reason there was not enough engine running time to verify both paths, before one had to take off. Perhaps if somebody had launched an ICBM with the airport being the target (I can certainly think of some UK airport cafes being a suitable target) and I had to get away quick 
I still can’t see a technical reason, for a typical low wing aircraft, for the fuel pump to be ON during tank change. I absolutely know that the TB20 doesn’t need that.
I think in most fuel injected aircraft with a well functioning mechanical pump and pipes it does not seem you will need boost pump ON on fuel tank change (assuming it is wet) once the engine at running at cruise rpm
Obviously, switching from a dry fuel thank, I am sure you will need the boost pump ON (even on a high wing aircraft )
