Any attack would be casual. Not direct, since a direct attack (fleets of ships etc) would revel the attacker and thus the attacker’s home world to others.
Penalty is always death, and that death would mean being sure the attack was successful: such as a light-speed, hyper-dense object striking the sun causing a nova, a dimensional strike reducing the solar system by one dimension, a strike that changes the local physics and so on, as a failed strike would reveal the attacker.
yes you’re right
It’s not the movies where INCREDIBLY ADVANCED civilizations have fighters that our jets can take out in dog fights :)
Their weapons would be UNGODLY in their destructive potential.
Or maybe, if they’re that advanced and saw us already, they decided that many, many thousands of years from now we could be dangerous so they have sent one of the weapons already.
I Imagine an attack with advanced alien technology against earth would be as simple as a GMO virus. Much cheaper and easier than a single nuke to accomplish.
“Babylon 5” actually had an episode on this. The probe carried a bomb and said answer all my questions or else I explode. It had very difficult questions they barely answered. The Captain realized that the probe was sent to DESTROY potential threats. That any aliens that COULD answer the questions and were advanced were to be wiped out by the bomb.