Depends on how the parties behaved in the past. There are a bunch of government entities which called police on me in the past when trying to work with them about discovered issues and as result also will just get anonymous 0-day drops in public forums for future issues.
I expect the responsible person listed for some specific application to react to an email about it to fix it, and not send me police. Why would I want to jump through hoops for doing them a favour?
Same applies also if there’s no easy way to send a mail to someone responsible.