first if you are talking a maf car setup to run a maf, you will usually never be able to get above idle
Wont hurt the car but will really make it non driveable.
If you really want something to work if using a stock style actuator just disconnect the actuator from the pipe puck arm
car will never make any boost not throw a SES and pretty much just drive as an NA car.
Now if you are talk a speed density setup then still wont hurt the car, it will run as if NA depending on how the VE tables are configured.
Not to mention that that is a lot of work for a valet mode.
If using a maf just disconnect it, it will throw a code but car will run like crap.
if speed density you could just remove the chip or flash your PCM with a no boost no timing tune