The sarcastic "thanks guys for the check 6" from a pilot dropping from the sky with wings absent scenario has occurred, as of late, somewhat frequently and leaves one to ponder a bit on the issue in some depth; when is it appropriate to check 6, or expect a check 6 warning from ones countrymen.
My belief is that most players are courteous and will cheerfully provide a helpful "check 6" warning to a fellow countrymen when noticing that individual is being pursued by an enemy, and especially when it appears he is not aware of the enemy behind.
However, in the classic fur ball, there may be so much chaos and compared to different players varying degrees of situational awareness, if you didn't get a check 6 warning, it might be because no one noticed you needed one. Personally, my own SA is enough to primarily make me aware of dangers around me, and if there is any "extra" SA to spare, I will try to be aware of dangers for others as well.
Furthermore, the 'check 6' isn't always a welcome thing. For example, when engaged with one opponent for a somewhat prolonged duration, an unwelcome 'check 6' may be considered negative if there is, in fact, no additional enemies joining the fight. Without regards to which end of the clock the countrymen is on, he may be distracted by an untimely 'check 6' forcing him to wonder if there is an additional enemy that he has not detected. If you note that your countrymen is obviously taking evasive action, or has been engaged with the enemy for a prolonged duration already, he is likely already aware of that single enemy on his six.
If your fellow countrymen is in pursuit of an enemy ahead of you, and there are no enemies perusing him, then it is also considered in bad form to 'check 6'. After all, he has the dominate position on the clock and might consider your 'check 6' an intentional means to distract him while he looks for an invisible enemy and you move in on his potential kill.
If your fellow countrymen has an enemy behind him over two miles away, and that enemy has obviously not selected a specific target or engaged your fellow countrymen yet, then this too might also be an inappropriate time to 'check 6.'
There can be too much 'check 6', and not enough 'check 6', so it is best to use this helpful aid in moderation where appropriate at your best judgment.
When do you want a 'check 6' warning, and when do you consider it unwelcome?
Do any of you think that the 'check 6' warning is misused, and with intent?
Do some players expect a 'check 6' in somewhat chaotic fur ball situations where others may be simply too consumed with their own imminent danger?