This is what we get for walking down a dark alley before 5 p.m.
There's a trope that young people may rob you if you walk down a dark alley at night. But, this caption suggests that if you go down before 5PM during the day old, people would rob you --- this references that old people tend to go bed early. This is funny because 1) we usually don't expect old people to be criminals (particularly these folks who look well off); and 2) the man seems quite nonchalant about the situation, accepting that it was their fault.