have waveform models signal when phase-marginalization is allowed
phase-marginalization in PE is only strictly valid when the waveform model satisfies certain assumptions. Back in the old days, those assumptions were common, but the new sophisticated models do not satisfy them. To aid PE users, therefore, provide an explicit mechanism that can be used to choose phase-marg (or not).
The goal, in @cjhaster words:
What I think I’d like is a function which returns a True/False “if and only if the waveform has *only (2,+-2) modes in the inertial frame”. The default setting in the PE codes should then rely on that function to activate/deactivate phase-marginalisation.
On top of that, we’d then add a flag for the PE codes that would overwrite the decision from the function, this would then allow for phase-marginalised analyses in the cases where the non(2,+-2) modes are negligible, but nominally still present. I guess we should print out a big warning when this flag is activated as well
This way we’d be be careful and proper with the default settings, and also force people who wants to play fast and loose to have to make an active choice to do so.