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For the VH911, RCA took the cheap way to improve cross-input isolation. It simply shorts the 3 unselected video inputs to ground, thus providing very high isolation. Unfortunately, if one of the inputs comes from a Y splitter, that Y splitter's other leg will also be grounded out. Technically, splitting a 75 ohm video signal with a passive Y splitter is not kosher (impedance matching is important at video frequencies), but for most applications, the signal degradation is trivial. It also means that an expensive active buffer will be needed if the video signal is to be split. This heavy-handed approach may damage (or overheat) some poorer designed video sources which may not handle a zero ohm load.
Interestingly, RCA did a better job on its 2 to 1 RCA selector (DT902AV). Here the unselected input is properly handled, switching the unused input to a 75 ohm dummy load, instead of ground. So it is caveat emptor, as you won't find this information in any specs.
Incidently, someone wrote that the selected indicator is not very bright. I would imagine so, given that the indicator is not a light scourse, but a reflection from a red-colored moving tab. Remember, this is a completely passive device so there wouldn't be power for an LED.
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