You're right and you're wrong. It's not that no one pays any attention. It's more like too many people, pay far too little attention. So while in the best of all possible worlds it might be a good idea, in this world too few people would be paying enough attention to it to make it worthwhile. And then the concept of 'Guest Star' would have to be explained to each of the ones that did. But keep right on thinking and submitting suggestions.
I'm only laughing on the outside
My smile is just skin deep
If you could see inside, I'm really crying
You might join me for a weep
My Roster
It's an interesting concept, and I do like the image you evoke with the idea. It's the "X-Men + Spiderman" sort of thing, classic crossovers. However...It's an oddball concept that probably wouldn't catch on very well with the masses. It would be better just to do it the old-fashioned way, finding SGs to work with now and then.
It's too bad this wouldn't catch on, people forget that this is a comic book game...Nobody does comic book stuff like this.
The off-beat space pirate...Capt. Stormrider (50+3 Elec/Storm Science Corruptor)
The mysterious Djinn...Emerald Dervish (50+1 DB/DA Magic Stalker)
The psychotic inventor...Dollmaster (50 Bot/FF Tech Mastermind)
Virtue Forever.
So you want a flag that says looking for team not super group? Well there is no looking for super group flag so the whole system which works quite well for those of us who use it. Sorry by default I feel I should be against that idea, see the nature of super groups is that bigger is better and more prestige is better, with my SG we invite friends only and people we team with on a semi regular basis who ask to join as you could imagine we are quite small a month old and only about 10 active players ... maybe 11 with a few people I have heard wanting to join atm. Now many SGs just want bigger numbers not caring about anything, these are the ones inviting you every time you join a team and if you think a flag asking them not to invite you will stop them you are kidding yourself.
Thinking in terms of 'guest-starring' in a comic spider-man has worked with the X-men a few times and was asked to join, he just declined. Spider-Man is the best and he was able to decline, so can you. Or be a little more forward thinking if you want a solo toon not in an SG name a super group identical to their name, with them as the only member ... it should clear a lot of that up
I'm not sure whether there are still a lot of occasional players who don't roll with a consistent Super Group, but I was thinking about how I like to team, and I call it guest starring.
My favorite in game experiences are when I'm the odd man out on a team of smart, cordinated heroes. I like seeing how they work as a team, and then applying myself where I can be most efficient (depending on my AT of course).
As a result, I'm often looking for existing teams.
I thought, what if I could have a search flag which says "Looking to guest star". It would imply that I wasn't seeking SuperGroup membership, but that I would like to join an existing team.
You know...now that I'm re-reading this, I think it would be underused. No one pays attention to those flags.