Hi, I too have got several of those messages now. I'd say that there are several red flags with those email texts. First, the greeting "Dear player". Official Jagex emails have your ingame name if I'm right. Second flag for me is that those messages came to my old email. Third, I know for sure that I myself have not gotten involved in any of the activities those messages claim. Fourth, I highly doubt Jagex is ever going to threaten someone with legal action without warning. And last, the link in the mail, while at first looking like a real rs domain, is not real. trying to access that link (on chrome) gave immediately a warning. I know, do not click any links in emails...
Ill add the mails I got so you can see what Im talking about.
"Please note: Due to a recent bug in our infraction system, some accounts may have received a void infraction. The majority of void infractions have been removed. We urge you to visit the appeal section to appeal any unjustified infractions received due to system errors. Kind regards, RuneScape Account Support