a rideable wind range and a "get back to land before you get killed" range.
When the wind starts exceeding a comfortable level, the best way to look for serious trouble is to get back to land before landing your kite. If you think you'd better "get back to land before you get killed" my suggestion is that you don't get back to land until after you've disabled your kite in the water. Just one guy's opinion, but if you spend some time reviewing deaths and injuries in our sport you'll find out that launching and landing in excessive winds (on land) are a significant factor in our morbidity and mortality. Convenience is great but safety is better. And it's a lot safer not to fly overpowered on land.
(I know this isn't exactly what you meant but I thought I'd point it out just in case it makes even one person think a bit before coming ashore while overpowered.)