Overly smart bilge pump switches?

Navagear found a solid state bilge pump switch that can discriminate between fuel/oil and water, so presumably you will not pump the bad stuff overboard. I’m just a wee bit skeptical about how well this works in the real world. What if there is just a little oil swirling around your bilge; might the switch shut down when you didn’t really want it to? A while back I tested SensaSwitch (above), another solid state “float” switch that I liked a lot. It does not claim to “discriminate” against hydrocarbons but one reader wrote in claiming that oil films made it stick on or off, which of course is what no-moving-part switches are supposed to avoid (my test didn’t include oil!). The company tried to investigate the claim but the guy said he’d thrown the switch away, and his email went dead, so this report is very much hearsay. Does anyone out there have either SensaSwitch or Water Smart Switch installed in their boat?