It may appear dubious, but given the conditions may not have been that reckless after all.
Here's another example:

The above took place in light wind and never went farther than about 150' from shore. The photo you mentioned shows similar conditions.
Just to see how bad the seamanship might have been, here are the
coast guard's recommendations on carrying capacity:
SAFE CARRIAGE FORMULA – If your boat is not
required to be equipped with a capacity plate, use this
formula to determine the number of people that can be
carried safely. NOTE: This formula is meant for good
weather and is a general guideline that does not include
equipment that is carried and will decrease the space
available for people.
L x W = PEOPLE
15
Plugging in the numbers: (16.75 x 6.25) / 15 = 6.979
I wouldn't suggest maxing out that formula when there's significant or unsteady wind, rough water, distance from shore or low water temps.