Riot as a whole usually bans scripters for being excessively reported in-game. Back when packet casting was still a thing, Cassiopeias were very easy to call out. People who spammed Xerath, Evades without any humanizer at all and the sort were usually banned within a month or two. Even though the tool itself may bypass Riot's AC, they actually review and punish users that are reported for scripting several times.
The main rule about safety is: If you're being caught, you're doing something wrong. If you're being called out in-game several times for landing every single impossible skillshot or dodging things that come at you through the fog, you're doing something wrong. Someone that just started playing Xerath/Cass/Any-godlike-scripting-champion and suddenly has a 100% winrate and manages to land every single spell is either on very strong drugs or scripting.
People who are caught are usually the same ones that (ab)use the most powerful and consequently obvious things ever made and expect no one to realize what's going on. When you're given a safe tool where the only way of being possibly banned is by abusing things yourself, it's your own fault if something goes wrong.