A guy I work with did the same thing to keep his stuff in up at his hunting land. He said that a few times he found that there were marks from someone trying to work on the locks, but never a problem. Until one day when he went up to the cabin. He opened the door and looked straight through to the woods behind the container. Yep they took a partner saw and cut an opening big enough to drive his 4 wheelers through.

My outfitter friend bought some and with his excavator buried the container in the side of a hill …
Only the door was exposed . When he left for the winter,he would park his big excavator up against the doors ,and remove the battery’s..
All his boats and motors were safe until he returned in the spring ,,,

That's 1 way to lock it up tight I guess

gonna need some kinds of AC in that thing in the summer, you might as well be in an oven.

If true, maybe such heat would be hard on an atv or snowmobile

I have one at the farm to store fencing tools, small tractor, mineral etc. It keeps the packrats and mice out. I just put one cheap padlock on hoping that if someone feels the need to take a peek inside, they'll just cut the $10 lock off and not destroy the closing mechanism or worse. I figure as good as cordless grinders and sawzall's are these days, it won't take long to get in no matter what locks are used if they are motivated. It's just a matter of how much damage they do to the shipping container.
I'd like to have another one.

Does anyone know where I can buy 1 that's only 10' long?

Looking at getting an 8 x16