I was half asleep when I posted my original response, so here's a more detailed explanation.
Front sight post focus is probably the most critical aspect of an accurate shot (equipment aside). Thus, it is extremely important to be able to see your front sight post as best as possible.
You note that the front sight post is not very 'crisp' sometimes. This is mainly due to light conditions. Light affects your sight picture, and also affects how your eye perceives the front sight post. You don't want your front sight post to be shiny, otherwise you will not be able to get a proper sight picture - bad focus.
And the way the light is reflected off the front sight post can also vary. In your case, you've noticed how the edges are not very crisp. This is mainly because the finish on the front sight post is reflecting light in various ways.
Thus, shooters will do something to blacken the front sight post. It works by making the front sight post darker/blacker and by making the finish on the front sight post consitent throughout. Also, blackening the sight will result in a matte/flat finish, which makes reflection of light very minimal, thus a more visible front sight post (black).
There are two main ways to blacken a sight: using smoke or spray on temporary paint. A smoker of some sort is preferred because the smoke residue does not build up anywhere near as fast as spray on finishes. It is possible for the spray on sight black to build up in layers, and thus, make your front sight post wider or taller, affecting your sight picture, or even your sight settings. Granted, as long as you clean off the sight black between matches, you'll be fine.
Anyway, this is why you see many shooters putting a flame near their front sight post before the event or even before each stage of fire.
Good luck at the tournament. Have fun. Stay safe.