Everyone invited, All ages....???????

I must vent. It makes me feel better. We received an email recently about a "group", shall we say, that was going to be formed for a short time. Everyone one is invited....all ages..all "jobs", etc. However when I inquired about this "group" I was told, in a similar statement....I don't think we will be needing anyone else to do that particular "job". OK, what does everyone invited, all ages mean? My familly member that was interested in this particular "job", doesn't usually want to be a part of something like this. So, when my family member mentioned being interested, I was thrilled. Upon finding out that this particular "job" was not needed, I asked how I was supposed to explain to my interested family member that he was not needed, after all the email did say...everyone invited..all ages. Needless to say a "job" was formed.
I'm not sure why my family member wasn't needed at first. Is it because the leader of the group didn't know that my family member could handle the "job"? Or did the leader just not want to find him something to do. I'm sure I am more aggravated about this than I need to be but....why send out and email saying everyone invited if you don't really need everyone?

Anyway, I know this probably doesn't make a lot of sense because I am so vague but it does make me feel better to have it written down. OOOHHH and the"job" my family member is doing made a big difference in the "group". In my opinion!!!! :) Thanks for letting me vent.