Great post and a great idea. After reading through, my initial reaction was that this is good, but instead of “for the summer” how about a Friday off once a month. That would prevent the loss of hours from occurring in one segment of the year.
On the flip side, being from the North East, winter can be very harsh. Three-day weekends would be less useful. “Summer Hours” allows employees to take the time when they can be most useful, weather wise. Then there’s the fact that kids are off school. One day less for the babysitter. :)