Edit
I personally like to trap bots behind doors and it works 9/ 10
I agree the timer is too fast.
If you were to pay attention, you could see that only buildings that can be abused; containing items, monsters, ores, beds and quest-related doors, close on their own.
All other doors are open and accessable.
Exhibit a
Bed, range, and air rune spawn are closed. Gaurd towers entering lumby castle, church and bob's axes are open.
I've heard iron axe fetch a great price in ah
Exhibit b
Cooks assistant quest, naturally spawned items, and a basement of spiders are closed. They spawn items, mobs and can be automated.
Goblins. The most obvious place people would bot, naturally they don't. Goblins never drop good armor.
Exhibit z
No one goes to draynor.
Now we arrive to Varrock, the largest city in the free-world. Fairly uninhabited the Npc-to-player ratio is about 50 to 3.
Here's my favorite house, free cabbage. This oddly shaped building that serves no purpose but to shield the Black-arm gang. The bar's always open for business. Swords are rarely bought at this store. All open and accessible.
Many buildings in Varrock have open doors. In this case, muggers may be breaking into them.
The other side, you DO have item spawns, leather armor and a log, the closed door is related to the phoenix gang quest, and buildings that are always vacant.
Very specific buildings have closing-doors, there is an excellent place to bank, cook and sleep. There we have a pink skirt, vital to the Prince rescue quest. Also, very fashionable.
There's also a training spot, that is open to the public.
Anvils East, rarely used even next to a bank. Possibly because it's different with NPC shops.
Anvils West, next to a bank are timed to close.
Hey, I am an Ultimate! Just ASK me "what's Ulti-mode"?