When investor confidence in a manager is low, suspending dealing is one of the tools which can be used to manage the outward flow; as we have just seen from Neil Woodford. 

But applying the gate isn't something to be done lightly. 

First, it can further erode investor confidence. Leading to a vicious circle.

Second, some investors (particularly those burnt in previous suspensions) will automatically respond to a gate by submitting a full redemption request in a bid to secure their position in the queue. 

Third, it may lead investors to ask about the validity of any suspension and its application. (This might be good news for lawyers...)

Fourth, the time and effort taken up in managing investors (and market) expectations is vast. Everyone will want to speak to the manager and his team; when the main thing he will want to be doing is actively managing the issues with the portfolio.

It will be interesting to see how this one plays out, and what lessons (if any) have been learnt over the past decade and more.