There is a way, I've stood out on the wing several times this season already, thanks to Boeing for the fantastic emergency exits on the NG (still shocks the cabin crew though, closing them seems to be difficult for most
). We've got the same paragraph in our manuals about the upper wing frost with the addition that 'this procedure is suspended until approval from the authorities'... The same problem comes up often though, airports without deicing facilities and a minute but still visible layer of frost on top - no good solution here unfortunately I suppose.