If using chlorinated water, I drain and screw the end tight. I'm not a biologist but it seems to me that keeps the chlorine from evaporating.
If I know it's well water, I drain and screw the ends just enough to keep critters out and let it get air. Common sense will tell you that it really doesn't dry out inside, at least not for a long time. A little air will keep some fungus from growing but I'm sure will help others.
When I sanitize my tanks, I pour a little in the hoses and slosh it from one end to the other and allow it to sit for a while
That has worked for me for years, but nothing says it the best way, it's just my way.
Either way, I don't leave the ends open for the bigger critters.
I do empty, dry, and then plug our water filter. Failed to do that one time after a Florida trip and about 2 months later, it took 2 hours to get the fungus out of the cracks.