i think you can get into -SL when leveling or someone wants you to. i remember back in 2.0 there were people in the chaos cave stealhing into you fire, then when you drop SL they came in and tried to kill you. nabbl why do i tell you this. you played this game longer then most of us :)
another point made by strife i think. that this change encourages griefing to some extend and only punishes players who actually care about SL.
and again i have to say (in NC terms: cry) about the fact that SL changes make no sense when someone can just log to a different character, kill you, come back with main character and say "hi". what the SL changes really do is encouraging players to level up another account and not following intended gameplay ie. staying true to a clan or faction and living with consequences.