Guys, we've been through this before. MC's contracts include geographical rights from the suppliers (fact), they can prosecute and will have the suppliers' backing so a civil rights action is always possible.
Why they may consider it: Their parent group (also called Multichoice) also owns Irdeto, I'm sure you know they're behind the security smartcards and distribute that system worldwide, they've got an example to set.
When they started they also only got much of the content we take for granted due to agreeing with American studios to do their best to constantly challenge piracy (all facts).
When it comes to why not, in this case not fact but rather as I see it - Even if they can get info past a VPN option, they can never prove that the end user knew of their rights entitlement, nor that user's intentions. Last I heard most use a VPN for privacy concerns.
Argue away though, there's no ways to make a solid case as it's never reached the courts.
Still best IMHO to stick to a legal service, then even less of a practical case is possible.