Wallpaper and Wallcoverings - Question on hanging border around corners in small room

I am hanging a border around a powder room with each of the four walls being six feet or less. Most of the advice I have read indicates that I should cut a section of the border for each wall. However, that generally is based on larger rooms. For this small powder room, should I cut the border for each wall, or can I wrap the border around each of the corners without cutting it? Since my spool is 15', I can actually cover all four corners in the room if I don't cut it. But will that be a problem?

You are most likely going to need to cut the corners no matter what. If you wrap them, when it dries, it will pucker out. It will also want to track off level as most corners are out of square. I would paste up the border, start by overlapping 1/4" at your start point. Run it down the wall. when you get to the corner, cut it dead in the corner. Then, lift that piece up slightly and underlap the rest of the border. Put the piece back down, then keep running down the next wall. Do the same until you get to the end, and overlap your 1st 1/4" lap.

Hope that makes sense.

Yes, that makes sense. It will be a bit more complicated because I have a design that repeats every 21", but that's no problem. Since my border is pre-pasted, do I have to do any additional pasting where the pieces overlap?

Yes, use a thin bead of vinyl-over-vinyl adhesive on the overlaps. I would also suggest thinning down some heavy duty clear wallcovering adhesive, and pasting the border with that. I don't trust the factory pre-paste, especially in a bathroom.