Could you add in a colour coding to the flag tooltip to indicate if you have that Flag.

When you hover over a flag (eg in the CL groups) the tooltip displays the flag and country.

It's a very trivial suggestion so go easy with the hate. >.<

(I was bored while looking at my CL draw and decided to look for flags I didn't have so that I could add them as friends to increase the chance of meeting them. )