While finding myself on a team of much less accomplished designers (at least to date, they may surpass me soon), I find that pairs often come to get me before they are doing something they aren't totally comfortable with. Also, the StandUpMeeting's we have often introduce new SimpleDesign's that could be made simpler.
We talk about alternate ways to do it, and the pair does it if they see the benefit (or I insist there is one... but usually it doesn't come to that). This does not break up the flow of ExtremeProgramming at all. In fact, I think it instills confidence in the others that what a pair can't do well, the team can. -- KenAuer