"Well, I'm pretty certain that if I stand out in the yard, spraying the garden hose in a solid jet, swaying right to left that the water at any instant forms an arc shape at peak angular rate. Each drop is traveling in a straight line, but the overall swath of water isn't straight. But you're right in that the drops themselves travel in a straight line. (and that light travels in a straight line.) I would like to retract my claim that light could go through a bent tube."
Except for the curvature caused by gravity, your curved tube wouldn't work, except to force the water into a curve. Each water droplet is traveling in a straight line. This is simple Newtonian physics, f=ma. What is your force that curves the water?
However, using the water source for a frame of reference, the droplets do curve.
No, they appear to curve.