A small amount of fuel from the sniffle after shutdown would suggest a standard Bendix type injection. Marvin and I don't get those drips. He has a SDS EFI, and I have an AFP constant flow with a purge valve.
The SDS won't allow flow into the intake port after shutdown because the injector pintles are closed.
A purge valve vents system fuel pressure to the return line. That allows the spring in the divider to close its outlet. The only fuel remaining which can reach the ports is the wee bit in the small diameter injector lines, and then (for the most part) only if it boils.
The small fuel risk with a standard Bendix style system (Bendix, Precision, Avstar) is 25~30 psi captured downstream of the engine driven pump after the engine stops turning. Several conditions must be met to put measurable fuel in the sump. First the engine has to stop with the fuel pump pushrod on the pump cam's base circle, because that allows the fuel pump spring to continue applying pressure to the diaphragm. Next, the pump's inlet poppet must be leak free, or the pressure would just vent back to the tank. Third, the mixture valve in the fuel controller has to have a leak rate. Most do, but the leak rate for a typical disk-style valve is quite low. Note even if the conditions line up, the most fuel the system can dump on its own into a closed, no sniffle horizontal plenum equals the volume of the pump...which is not going to be a problem.
So, forget the few drops you might see after parking. The real reason for a sniffle valve is to drain away excess fuel from boost pump operation prior to start. Consider the fellow who flips on the pump, then gets distracted. With a gallon or so in the sump plenum, there's a pretty good chance of sucking enough up an intake pipe to cause a hydraulic lock, and bend a rod.
The other potential risk is water, like filling the horizontal sump plenum with a hose while washing, or a taildragger with a snorkel parked just the wrong way in a rainstorm. Like Marvin, I'm not going to tell you to remove yours. You'll need to think about the details and decide for yourself.