While putting final tweaks on my RAAF Intruders, I noticed that when I tweaked the Textureset.ini, I would lose the Aussie flag from the tail.
Before:
After:
You'll note that there are actually six separate decals on the tail node (no reverses, but L/R versions of each decal): the squadron logo, the fin flash, and the flag at the top of the tail. Though not complaining, I couldn't figure out why it was even working in the first place, much less what I was doing to break it.
Long story short, when I was adjusting the specular/glossiness/reflection values, non-zero values for all three would cause the last decal (the flag) to disappear. Resetting reflection to 0.0 would cause the flag to reappear.
I haven't yet tested this with the other values; I can release this just fine with a 0 reflection value by keeping the specular and glossiness values up. I just thought that people might be interested in a way to stretch the decal-mesh limit.