The (ultra) slow roll is a great skill to have, and when you get it nailed, starting and stopping need not produce anymore stress on a tandem than they do on a single. Part of the problem (I think) is that the average team just does not get the hours in to really get these skills dialed in. We are a blind stoker, partially sighted captain team, and are 99% car free, so every weekday commute is on a tandem, plus errands, shopping, recreation. Adds up to quite a bit of time to make it all pretty instinctive.