Whilst sending a tea boy out to take a snap doesn’t sound particularly right (do tea boys exist?) it does show how the large libraries have successfully setup the mindset of picture buyers.
http://www.theregister.co.uk/2010/06/29/bbc_snap/
Of course its not quite as simple as this, the BBC could well have a fixed deal where they pay a set fee to Getty and so sending someone outside would just add to costs, are you old enough to remember when things were a bit more simple?
Stephen