No, this is not some new Homeland Security Initiative.
I talked with Steven Gloor of Vesper Marine quite a bit before deciding on the Vesper Marine 850 last October. I wanted to stick with one masthead antenna. He counseled us to use their SP-160 powered (amplified) splitter as most of their testing indicated a standard splitter would deliver uneven performance if a connection was even allowed.
When I later did a SWR test on our VHF+AM-FM splitter, I came to the same conclusion. Our ICOM could blast through the slight impedance, a low wattage AIS, might have problems. We now have a Vesper Marine SP-160 AIS+VHF+AM-FM splitter.
I didn’t bother risking damage to the unit by even trying the old splitter.
When wiring the splitter, I decided to switch it in parallel with the VHF, Stereo, and AIS. This way when any one of the three is switched on, the splitter will be as well. The SP-160 is still fuse protected between the junction of the three red parallel wires and splitter. I bounced this off Vesper Marine and received a strong affirmative.