[DTV]

Thing is these things happen and always have. No one takes them that seriously, and they end up on the Christmas tape and Aunties Bloomers. To say that it shows a decline in standards is just nonsense

Absolutely. I mean, during the 1970s, Peter Woods famously presented a BBC1 news bulletin so drunk he was slurring his words (and, even if not to that state, that's far from the only occasion that newsreaders have gone drinking before going on air). As for being aware you're in a live studio, even seasoned-pros like Peter Sissons and Sue Lawley were definitely known to have made comments while miced up that wouldn't have gone down well had they been broadcast (e.g., "she's even got new tits").

As for the professionalism of presenters, the years of double-headed presentation are filled with anecdotes of one presenter trying to put the other one off and Jeremy Paxman would deliberately do things like messing up the Newsnight Scotland opt point purely because he didn't agree with it. On the latter, I'd argue that repeatedly undermining colleagues because of your personal views is more serious than being caught once messing around with colleagues during a brief break in your multi-hour high-pressure shift.