@Tosche - You always have amazing answers, thanks!
I know that adding non Latin glyphs in Latin kerning groups results in useless pairs, but it does make life a bit easier.
Some time ago, I posted a thread about Vietnamese: I had made a font, kerned it and then decided to add Vietnamese. I added those glyphs to the kerning groups and then discovered that the Vietnamese glyphs did not follow the rest. I think you told me that I should have added Vietnamese BEFORE kerning… as in, the font had kerning and did not accept new glyphs being added…
You can find the thread here.