In the UK, the set top boxes used for digital satellite and digital cable already contain the facility for the broadcaster to turn on or off Macrovision encoding of the composite analogue output signal, preventing recording with standard VCRs. This is used on all pay-per-view movies and I think other pay-per-view events too.

At one time one of the Asian channels (Sony Entertainment Television Asia?) turned it on for all their broadcasts but had such opposition from viewers no longer able to record their favourite shows that they were forced to turn it off.