Okay, this should have been my first and most important question.
For a long time I've been waiting 'til clor is zero and ph/alk are neutral and then draining straight to lawn and plant area.
Total no-no, or hey thats like tap water w/ a little "organic material" mixed in?Plants seem content, but who knows over time.
Hell I'm driving a biodiesel truck. Wanna do right by mama.
I know this drainage practice is prohibited by local codes.

guess either the flora is all good or its a chemical company conspiracy.

if PH is neutral, and chlorine and bromine are 0, plants will like it more than rainwater. Go ahead. Never heard of local codes that prohibit draining a spa, but even if they exist, if the water is balanced, go for it.