All Wing Chun practitioners should be doing live testing. As far as cross training, that's an option for those practitioners who feel they need it.But there are wing chun systems that do address that issue with live testing, cross training and seeking out expert advice.
Being a practical fighting system is the heart of Wing Chun methodology, along with aliveness and adaptability.Being a practical fighting system is definitely part of at least some wing chun methodology
However, I don't see how any of this is relevant to my comment above. The statement I quoted from CYNIK75 has zero contribution to the Wing Chun community.