It's just as likely that archeologists unaffiliated with BBC came up with this theory months or even years earlier, wanted funding and a bit of publicity for their pet project, got hooked up with BBC, and scheduled the most important part of the excavation to coincide with the arrival of the TV crew as per the funding agreement. The whole point is to maximize the likelihood that an interesting discovery will take place during filming. NatGeo does this all the time, and I'm sure BBC does, too.