Ive been to Tamarindo 4 times in last 2 years.
No troubles, just dont make yourself an easy mark. New Orleans or Houston much higher chance of getting robbed!
Friday night at your hotel will get loud, just roll with it and have a good time.
Walk to Grande or get a ride to Avallenas... head south for heavier waves Negra, Marbella.
Get lunch from the lady selling home cooked meals out of the back of her car... good stuff!