Toilet help!

Those factory clamps around the pipe are probably the source of you re leak my suggestion is remove the old clamps and install new hose clamps at those fittings you can get the clamps at any automobile parts store that just might fix your  issue

Am I missing something? There appears to be splice of some type wire the line goes from flexible piping to rigid piping.  Just get a plug or cap, whichever works, of the proper size, and plug or cap the flexible tubing right at that splice.

You didn't really say where exactly the leak is so I'm assuming it's at the T junction on the pipe. First realize that T junction means there is more than one fixture served water by that pipe that comes out of the floor.My guess is that T feeds a bathroom sink so you can't just cut and cap the pipe.

Second is unless you are going to a dry toilet this minute you should just fix the leak so you can use water in the RV.

I would look into getting a Sharkbite fitting from Home Depot. Link  Link is for a T fitting but they also have 90's and straight fittings. They also sell lengths of the pipe in case you make a mistake and need to replace a section. Then carefully cut the leaking joint out and replace with the Sharkbite fitting. The beauty of the fitting is it's easy to use.

Cut the plastic tube as square as you can.

Trim the lengths of the tubes to the length that makes sure the tubes can slide into the joint and bottom out in the fitting.
Press the Sharkbite onto the tubes. It's just a push on no need to tighten or crimp anything.

Turn on the water and check for leaks.

It is probably easier to take a look at it and see why it is leaking and fix it rather than trying to cap it off

If you just want to cap it.

• Cut the tube just below the T
• Use a sharp knife or razor blade to make the cut a square and flat as you can
• Press on a sharkbite fitting.

You can use one of these and just leave the valve turned off. Link 

Or one of these to just cap it off. Link 

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