Unfortunately there's nothing you can do to stop someone from opening a flag on you, but as Loyce pointed out, the flags are of little to no importance thanks to the lack of status of the accounts supporting it. Not much more to be done about Bankera at this point anyway!
I think flags disappear after, what was it? 90 or 180 days without support? But since the flags against us do technically have support, I don't think they're going anywhere, unfortunately...
Who knows, maybe in the future modifications will be made that allow certain higher ranked members to remove certain types of flags.
Keeping that aside you are right when you say the flags have little or no support and therefore little relevance regardless of whether they stay put or not.