Sloping tops: while most lockers have flat tops, some manufacturers offer the option of sloping tops to their range of lockers. The slope may be of either 30 degrees or 45 degrees to the horizontal, sloping towards the front, and the purpose of this is to make it impossible to store items on top of the lockers, or to make it harder for dust or other debris to accumulate there. This is an important factor in places like food-processing factories or restaurants where hygiene requirements must be met.
There are plenty of convenient places to store your luggage in Denver, from downtown to Lincoln street to Capitol Hill and Commons park. The cost is just US$6 per day, and check in time is just 3 minutes. So basically, in the same time it took to make that instant cup of Ramen before rushing to the airport, you can be in and out the door with no luggage to weigh you down.
Stored my luggage for several hours at Lugden. Great location just across the street from Union Station. Spoke with the owner and he said he owns the parking spot so they are always there during the day. Prices were reasonable and I felt comfortable storing my bags there while I explored Denver. The owner was nice and gave me coupons for some local businesses.
Other advocates of lockerless schools also cite reasons such as reducing noise by eliminating the clang of dozens of locker doors, or creating a more appealing environment aesthetically. It has also been claimed that removing lockers provides good training for students by forcing them to be more efficient in managing their books, and taking the time to plan what books they will need, and carrying only those ones.