tubular/cylindrical lock 'covers'? What's the deal? Calling all locksmiths!

Factual Questions
1

I’m unsure of the correct terminology but today I saw a cylindrical (tubular) lock (the 7-pin or 8-pin type) which had a flat metal circular ‘cover’ over the lock itself. This lock was on a vending machine… Pepsi, IIRC.

In any regard, after I got my ice cold POP (not soda), I played with it for a second and it doesn’t move or turn.

What did I see? What is the purpose of this and how do they open the machines if this covers the lock?

2

I can at least answer the purpose I think, those locks SUCK!

The lock type in question (correct?), the tool that opens it gently, ~$75.00, and the tool that opens it forever $35.95.

How many SODA (not pop :D) machine coin boxes do you need to open before you start seeing a profit?

CMC +fnord!