What Does The Phrase "Watch Your Top Knot" Mean?

I believe it is a form of a cautioning good-bye. Scalping may be plausible but I believe the term, as used in the movie "Jeremiah Johnson", refers to the last knot tied on a diamond hitch. If that knot becomes undone the diamond hitch will come apart and your pack animal load will fall off that animal. So, watch your top knot and good-bye.

It means to watch what you have worked for, especially presently. Everything you have worked for and that you think is secure, could all fall apart in your plan A if someone or something tries to jeapordize your safety net. Nip it in the bud by keeping an eye on the final things you have done so you can stay tighly grounded. IF the top knot comes loose, then everything you built to get there can become weaken and shaky. Watch the top knot, check it daily, and then everything you harvest will reap great reward, just as you had planned.

It basically means to take care of yourself and watch your head. Back in the day when people were afraid of Indians scalping them, they would say to a friend "watch your top knot".

Top⋅knot  [top-not]  Show IPA
–noun
1. A tuft of hair growing on the top of the head.
2. Hair fashioned into a knob or ball on top of the head.
3. A tuft or crest of feathers on the head of a bird.
4. A knot or bow of ribbon worn on the top of the head.
Origin:
1680–90; top 1 + knot 1  
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.

The term was probably from Jeremiah Johnson movie meaning don't get scalped ie. Your top knot is the last knot in a ponytail that attaches to your head. If your top knot is gone, you have just been scalped...

I would think it would mean keep you eye on the goal (reaching the top knot) but not sure.