IMO there is nothing wrong with invading the pitch especially after a massive cup win. Provided that,
A The opposition fans don't wade onto the pitch as well looking for violence
B You don't attack the players or the coaching staff. There doesn't appear to be any evidence of Rangers players or coaches attacked, only rumours.
As long as the fans are happily celebrating with there players and having a great time there shouldn't be any cause for concern. Football is for the fans to celebrate their teams triumphs and I know how relieved and joyous Hibs fans will be after getting that particular monkey off their back.
P.S the fact that Rangers refused to collect their medals after the match citing safety issues is a sheer embarrassment and shows them to be the sore losers that they are.
That is all. Congratulations Hibees !! I look forward to visiting you lot next season.