Astir,
...there's a nasty period with an aerotowed flexwing near the ground where a launch failure is virtually unrecoverable.
That shouldn't be the case.
When I learnt to aerotow on a hang glider (90s) the trikes had a higher stall speed & flew faster than the gliders. We took off before the trike & had to hold the bar well back (ie stick forward/nose down) to stay in the correct position. If the weak link broke, there should be plenty of airspeed to remain in control & land ahead from 30'.
There was a chap on the same aerotow course as me who had a habit of letting go of the uprights & reaching for the basebar pretty much both hands at the same time. He was warned that this was not a good technique & inevitably, a couple of flights later, his two-handed grab for the basebar missed. The glider shot up into the perfect nil wind flare, nose to the sky, before crashing down from 20 or 30'. He was concussed but otherwise unharmed; the glider had the usual collection of broken aliminium.
I think lockout is more of a winch launch phenomenon. I've never heard of it during an aerotow, but it's been a while since I did any HG.