Aside from Halloween being Irish and a good handfull of Pirates originating from there as well, I really can;t find a noteworthy reason to do a Pirate them (Let's be honest, I seldom if ever have a "theme" in a general sense of the word, but make it all work last minute, since I decorate the day-of)
Honestly, I could probably pull it off, considering the locality that I live in.
However, it is always nice to see. This year, I went through Celebration, FL (A city of Multi-Millionaires) to see the houses and the synchronized music/light displays that often encompass multiple homes. It was pleasant to get compliments from the locals that my car was "a better display" than the houses I was listening to/watching. Anyhow, there is this fellow who does an entire visage over his mammoth house and decorates all-out with skeleton Pirates everywhere. While impressive, it is so only in girth, as with the obvious time and money involved, I feel we from the Forum could do much better. Maybe I can dig up some photos. I didn't take any, but may just know someone who does.