I've done this many times and for extended periods of time while building/modifying guitars, with no issue whatsoever. As long as the neck isn't exposed to too much humidity or heat (with or without strings) it'll be fine. Assuming it's been properly built and coated/varnished. The floyd trems are a good example of why on some guitars it's a pain in the butt to restring if you take off all the strings. I've got an archtop with a floating bridge, I never take off all the strings on that one. Same with the banjo. But only because it's annoying to have to reposition the bridge. I understand your point. But if you think in detail the strings make strength over the neck, to give balance and maintain that.If you remove all the strings, that strength will be lost and the neck can be bend backwards.Of course, this not happen from the day to the night.Infact, if you store the guitar on good place, like you say, avoiding humidity, sun, etc you will retrase that effect.But in my experience this is not a recommended idea.