'Creating a problem' : I think that would depend on the boat and conditions ? Some boats are so 'rudder-dependent' that a 'broken' (and lifted) rudder would be a problem, depending on the direction you wanted to go.

Good point, and I paddled a rental boat that had the rudder removed "because they get broken" a few years ago; it was so bad I had to leave the group and return to the dock. Impossible to steer in a straight line.

I don't know exactly what you mean by 'special' -

By "anything special about the water . . . " I was thinking of stuff like shoal water or rocks that would need a flip-up rudder, a sandy bottom that could gum-up a complicated retraction mechanism, or dense weed that can wrap around the blade. I have all of the above where I paddle, so a tapered flip-up rudder with the hardware above the deck works best, ugly though it may be and sadly lacking in style. The taper lets the weeds slip off, the flip-up feature glides over rocks and actually steers well if it contacts the sand or mud bottom, and not much can reach the mechanics.