It's standard practice in vision mixers (production switchers in the US) to replace the entire sync and blanking interval. This ensures that the output has consistent sync, burst and blanking. Hence VBI information will not normally pass through a vision mixer.
Same is true in a SDI environment. If a system needs to pass embedded packets these are normally passed through a sidechain. Often decoded and re-encoded.
Most timebase correctors will also replace the entire sync and blanking interval. Back in the 1990s/early noughties I designed a number of TBC/frame synchronisers for G2 Video Systems. We weren't supposed to mention that they would effectively remove macrovision. Our official line when asked about macrovision was "not something we've considered or tested". This was actually true, we hadn't thought about it in the design and I'm not sure we ever ran any formal tests. It's just people found that it did remove macrovision
Hence both vision mixers and TBCs will usually remove macrovision.