There's something strange about this sentence. It contains a tab character when extracted from the database (and when exported to a CSV file), even though it isn't displayed with one above. Do you remember how you typed it in, or perhaps copied and pasted it?

@NNC tag can be deleted, it's OK

CK, you're right.

Deleted @NNC tag and added OK tag.

Why would people who have a bad command of a language add OK tags anyway? :?

In this case, I added it because Impersonator said the sentence was OK.

The tab was not present in the first version of the sentence. It was introduced in the first edit.

> The same reason people who have a bad
> command of a language add sentences in
> that language.

I have to disagree.

The main reasons people add sentences in languages they don’t know well are:
a) to make sentences in their native language more accessible (because a bad translation is better than no translation),
b) to practice a foreign languages.

These reasons do not apply to OK tags at all.

Your points may be valid (I could argue, but that’s not my point), but what I wanted to point out is:
— there are several reasons why people may add sentences in a foreign language;
— there are no reasons why people would add OK tag if they're not sure.

So,
— if someone adds a foreign sentence, she may not have malicious intentions,
— if someone is adding OK tags to a sentences when she can’t check their validity (e.g. when she asked a native speaker), it’s clearly a sabotage and should be handled as such.

"— if someone is adding OK tags to a sentences when she can’t check their validity (e.g. when she asked a native speaker), it’s clearly a sabotage and should be handled as such. "

Well, it sometimes could be done with a good intentions.
For example, there are many correct and simple non-native's sentences in the English corpus. When someone who has an advanced level of English see something like "I'm a teacher" created by untrustworthed user he or she can tag it OK even unconsciously.

Personalization of tags can be a good solution to avoid mistakes.