Almost any MSC that has shops where payments in cash are common, plus those with hotel shops that require a security assessment (lost key scenario). so: parking lots and garages; money transfer operations; ; public transportation; restaurants (especially breakfast buffets); airport venues or all sorts; and a variety of cash transactions in hotels. In addition, some situations where cash ot something small of value is "exposed" such as items left in a vehicle, cash or items left in a hotel room, etc. These are somewhat less common.
As for which MSCs, it really is all over the map because any client of the types mentioned may add a cash integrity or security component to the assignment without otherwise changing anything else.
Based in MD, near DC
Shopping from the Carolinas to New York
Have video cam; will travel
Poor customer service? Don't get mad; get video.