I know that in jazz, we have numerous scale options over any given chord.
If we have a C major 7 and want an alternative to playing C Ionian, we pick a different scale that has the same 3rd and 7th and use that to add extra colour. Alternatives in this case are often Lydian, Lydian augmented and harmonic major.
Learning recently about 'avoid notes', using these scales seem to contradict some of the 'rules'. The sharp 5 in Lydian augmented will clash with the perfect 5th (essentially as a minor 2nd). Likewise, the flat 6 of harmonic major will also 'clash' in the same way. However, if we then 'avoid' these notes, then there is no point in picking either scale as you will just be left with conventional Lydian and Ionian.
Do we therefore talk about 'avoid notes' only in a different context to this sort of modal mixture?