  We study the effects of bulk-edge Coulomb coupling on quantum Hall
Fabry-Perot interferometers. We find that these effects can be appreciable in
devices which would not usually be associated with strong bulk-edge Coulomb
coupling, provided the devices in question exhibit certain fractional plateaus.
With this in mind, we analyze recent experiments at $\nu=5/2$ by taking into
account a tunnel coupling between localized bulk Majorana states and Majorana
edge states. We find that these experimental data are consistent with the
widely held view that the $\nu=5/2$ state harbors Moore-Read topological order.
However, experiments may have measured Coulomb effects rather than an `even-odd
effect' due to non-abelian braiding.
