[2019] Jagex, please don't implement a Line of Sight update without polling it

You'll note the changes now only effect PvP which is to specifically fix an issue where 1 player may attack the other without the possibility of retaliation despite looking like retaliation can occur.

I'm going to guess you may not have read the news post today. Have a read over this section and your worries will be gone.

This week the beta continues but with a new version of the line-of-sight algorithm. Now, when a player is not interacting with another player, the existing live algorithm is used, meaning the behaviour in PvM situations will not change. When interacting with other players, the new algorithm will be used. This will prevent one-way safe spots in PVP.