You can easily see what systems Triglavian invasions are happening in. You also have cloaked time after jumping through a gate that gives you plenty of time to warp away from the bad NPCs. Like plenty of time. Sounds to me like your friend put it on autopilot and slow flew in, or jumped through the gate and just sat around waiting until his cloak ran out and he was attacked.
AKA: User error.
Hell I am new to this game as well, quite confused by a lot of it, and making mistakes, but the amount of whining in this thread is insane.
High security does not mean safe. The Only safe system is the starter systems and the sisters of Eve arc. And those are supposed to be safe from other players being jerks. Hi sec though, is not safe sec as you call it.
Unlike low/null/worm space, CONCORD gets justice for wrong doing, they don’t protect. But it’s for PVP wrongdoing not PVE.
Low sec has limited security and it’s mainly faction police, not CONCORD.
Your friend either took his time warping away or as mentioned used autopilot. I’ve entered systems with triglavians on gate in my Battleship and can warp away.
CCP does have plans coming up, though they were vague in their message that CONCORD is fed up with intrusive capsuleers, so not sure what that means for hisec as of yet.