Running Light Replacement Bulb

None of those are recreational boats, though. Although that third one look likes a cruise boat, so I'm sure there's lot's of "recreation" going on onboard there!

The rule is no different for recreational boats. It doesn't say you can't have any other lights it says that other lights must not obscure, be mistaken for, or change the meaning of proper navigation lights.
 
The rule is no different for recreational boats. It doesn't say you can't have any other lights it says that other lights must not obscure, be mistaken for, or change the meaning of proper navigation lights.
I think we're on the same page, here. The rule that we're referring to/talking about is FOR recreational boats. Other boats/ships/active fishing vessels have different reg's that they can follow.