Why some HD content is "hidden"

Just picked this up from the newsgroup virginmedia.support.tv:

We have now received an update from our Support Team and they wished to thank you for your feedback. Please read through the reply below:

All HD cannot be put into the same folder as some are transactional (Pay Per View), some content is free only to XL customers. Our current architecture cannot support mixed propositions in the same folder.

We are aware however that the current way we are managing HD in the user interface is not as intuitive as it should be and we are actively looking at how better to organise this. However we will always want to put HD programming next to its SD counterpart where possible, as this benefit customers looking for a film title( for example) and seeing there is also a HD version available.