It could also be used at various geocaching events North and South.
Also Geocaching Ireland have a rather bad logo, (Although the shop has a pretty good one):
A Slightly better one:
But if it weren't for the text, there is still nothing that would let you know its about geocaching. So here is my proposal for a Geocaching Ireland flag:
Its a variation of the banner of the Irish coat of arms, of a gold harp on blue field. Towards the hoist a celtic knot pattern is in orange. The hoist is green. I know there are more than three colours but they all come from the Grocaching.com logo (although in slightly different shades):
I think the flag is rather unique, and the colours are adequate symbolism, however the international Geocaching symbol (on which the logo is based) could be added to the canton:
Although I think I prefer it without the symbol,
What do you think, please let me know in comments.