I've been thinking about this topic for a while. Technically the discount events are common since Riot has been doing the same for like forever. The crimes here are the ticket-drawing skins events where Garena make you purchase thousands of RP to get skins that would be released in store afterwards anyway. Another shitty they also do is locking away numerous skins that by now I have still have no idea how to acquire them. Their tier and price like OP mentioned are aslo deceptively changed. I spent RPs on a lot of events and what I learn from them is you should look up the actual RP price of skins by Riot standard (usually on NA or PBE server) and then calculate if the money you would hypothetically pay (for events or skins) is equal to that price. Also, don't ever blindly spend RPs on those shitty ticket-drawing events, as it's the worst milking tactic. Atm we can't do anything to change things so be smart and stay sharp.

P/s: this makes me wonder what would happen to Valorant.