Brands, social media & Twitter mishaps

I was recently asked to share my opinion on whether agencies and/or brands are risking reputations their
and business by putting interns/junior execs in charge of client communications. My response is below is you can read the full article on The Drum.
Many companies fall foul in believing that social media can be a casual activity for a member of staff to perform in addition to their other jobs, but as with all marketing and communication activity it requires structure and planning in order to avoid disasters.
It is vital to remember that on Twitter companies are communicating and sharing information with people who have actively seeked them out and, in many cases, see their tweets immediately and share with their peers within seconds of the tweet being published, meaning they no longer have control of it.
For this reason the people responsible for tweeting need clear instructions on how to manage their
Twitter activity, especially if it is the responsibility of an intern or junior exec.
It is best policy that the person tweeting should not log into any other accounts from the computer they are working from, in many cases if people want to send personal tweets they can be done from their phones and avoid cases like Chrysler.
What do you think - how should brands prevent this type of slip up?