I wouldn't be against it (a cougars and kittens event) though I'd be unlikely to attend. I know quite a few women who are attracted to women 15+ years their junior. I'm not that old so that's pretty young
The problem is meeting those women. In your 20's and 30's you can still go to bars and feel relatively comfortable. In your 40's/50's what are you going to get out of a bar full of drunk women, spilled beer and immature 18 year old's? I'm having a hard enough time now and many of my friends are still partying!
Far better to organise your own night so you can meet women in relative civility.