I would like some clarification, desirably from:
Community Helper, Player, Forum, or Jagex moderator, on the question:
Is setting up a fresh mail address, then create alt for yourself trough the recruit a friend system,
Then buy 2x bond on the alt, and redeem for 1 months membership, to get the
10% xp raf scroll on the main account... Against the RS Rules?
Could making raf alts result in a ban, or any other offenses applied to the main account?
No, it is not against the rules to create your own "friends" accounts. Plenty of players have done so in the past.
However, Jagex has made it more attractive to have genuine friends playing with you instead of just creating your own "friends".
Look up 'Recruit a Friend' on the RuneScape Wiki - https://runescape.wiki/ and you will get more detail.