After you get snipped, it's potentially weeks/months before you are shooting blanks, a switch like this is less of babies/no babies and more like babies/accidental babies.
The relevant part.
“The binary nature of the Bimek SLV might make it seem that you can switch off your potency at will, but the body will need time to flush existing sperm out of the system, as it were. The ever-helpful FAQ says that it may take up to three months, or “until about your 30th ejaculation.” Whichever comes first is a question only you can answer.”
When I got mine, the doc said I should wait about two weeks then "ejaculate as frequently as possible" before returning for the scheduled checkup/semen test.
To clarify why, it's because sperm travels through those tubes for at least 5 days before reaching maturity and then once in position can be ejaculated by a pressure differential caused by the prostate (that bulb thing between the balls and urethra). So an effective switch with an instant effect would need to be placed before but directly adjacent to the prostate which could have potential complications when the prostate attempts to dry fire with the feed shuttered.
The solution is clearly to add a synthetic pressure bladder. (Don't, I'm joking).
This was my first thought. I could see this being a medical procedure in place of a vasectomy. Get switch (or something less likely to get bumped) installed and set to off. Then when you want to have kids, another procedure to turn the switch on.
People keep looking for a quick fix for male sperm control, I didn't think it is possible. At least not as a off and on solution that keeps coming up.