  We give a new, short computation of pairing probabilities for multiple
chordal interfaces in the critical Ising model, the harmonic explorer, and for
multiple level lines of the Gaussian free field. The core of the argument are
the convexity and uniqueness properties of local multiple SLE$(\kappa)$
measures, valid for all $\kappa > 0$ and thus in principle applicable for any
underlying random curve model, once suitably connected to local multiple SLEs.
