This is definite loopholing.

1. There is no rule stating that the sign has to be exactly 'BUILDING"
2. You broke the rule, you deal with it.
3. BUiLDING counts as a building sign.
4. The rule states it needs to be in LARGE font. Doesn't mean it has to be capitalised.
5. The rule also states that it needs to be spelt as 'BUILDING.' Not EXACTLY.
6. This is logic.
7. Too many points.
8. Others, including me use 'Building'. What you're saying is that they can simply add raid-able entities in their base because of an invalid sign?
9. This warning is valid, your reasoning isn't.

This is definite loopholing. 1. There is no rule stating that the sign has to be exactly 'BUILDING" 2. You broke the rule, you deal with it. 3. BUiLDING counts as a building sign. 4. The rule states it needs to be in LARGE font. Doesn't mean it has to be capitalised. 5. The rule also states that it needs to be spelt as 'BUILDING.' Not EXACTLY. 6. This is logic. 7. Too many points. 8. Others, including me use 'Building'. What you're saying is that they can simply add raid-able entities in their base because of an invalid sign? 9. This warning is valid, your reasoning isn't.