My goodness, I didn't mean to create an argument. I thought I was offering OP sound advice.
I got this tip back when we were renting TTs in the 90's. It was their rule to always leave water in the bowl 24/7 no matter what. He stressed the point and was within their written instructions every time. I never asked why, I just did it. I concluded that he owns about 20 units so he must know something.
I have followed his advice for the past 20 yrs without issue. But then again I haven't left mine dry for the past 20 yrs for a comparison data point so I have nothing else to base this on.
Now I can ASSUME it doesn't matter but I will keep doing as I have been in silence.