So, I'm driving along about 45 with the soft top on and the windows up (very rare for me) and notice a little draft on my neck. "Hmmm..." I reach above me to see if I can work out where it's coming from. A little poke to the soft top and the passenger side comes unclipped, folds back on itself and the heavy part hits the roll bar with an almighty THWACK before it all starts flapping around. Hey presto! A Half Top! Luckily the driver's side stayed attached and I didn't lose the whole thing underneath a semi truck. Also, the two cross pieces may have stopped it hitting me on the head.
I had checked the top before driving but obviously (duh) not thoroughly enough. We do alternate between soft-on and off a lot in these thunderstormy days.
Tesla Roadster For Dummies will need a box out: "if your soft top seems to be drafty, do NOT poke it with your finger as this may void your warranty". Good advice.