I just got this in a email
Japanese eye test
If you cannot decipher anything, then try pulling the corner of both your eyes, as if you were Japanese and read again. It works.
You could flag them down (make sure you have a canned drink/water) and offer them
a cold drink while you thank them for their service!
p.s. they are not used to that and may think you are inebriated
(speaking from experience)