The manufacturers were quoted on that news program as saying that the
capping could have been put in place on day 1, and TFL were unable to give
any reason why it hadn't been done (They refused to appear on that report
or issue any statement).

For capping to have worked "on day 1", Oyster would have to have been fully
functional on buses "on day 1", and the regulars on this group know all about
the teething problems of that rollout. I suspect the capping rollout will not
be as trouble-free as the above glib statement suggests.

I emailed TfL a while back asking why capping hadn't been implemented. Their
reply blamed trouble with testing:

"Testing of capping capabilities across the thousands of readers at tube stations,

on all busses, DLR and Tramlink has been far more complex and long-winded

than anticipated. This does not excuse, however the claims made by various

representatives of Transport for London that capping would be available a lot

sooner than it actually will be."