www.CostaRicaTicas.com

So the common factor is walking after dusk? Is it the shift or the low light? Then I recommend carrying a SureFire flashlight and when the police approach, turn on the light and if asked why you are turning on the light tell them you wanted them to see you weren't a threat. You can get a high lumens flashlight that is small, but powerful enough to light up the park. If they are up to no good they won't want the light drawing attention to them. Don't point it at them just illuminate the area and look curious as hell. You may even give them your flashlight when they see how bright it is instead of your money. There are cheaper brands, but I use SureFire.

http://www.surefire.com/illumination/la ... ights.html

You carry around a $100 flashlight? They will take it along with your money.

I don't buy that "it was my turn" stuff. It should never be your turn if you take the proper precautions. Don't walk around after dark, or even at dusk. Following this simple advice will eliminate 99% of possible bad situations you could get into.