Happy New year, Codeforces.
I had this idea for about a month. I heard problem setters complaining about some people used their coach mode authority to enlarge some problems' TL in the Gym just for letting their submissions passed. What's worse, these guys even forgot to change it back, which causes some troubles for participants afterwards.
Moreover, I also have similar experience. Back in 2020, I did SWERC2019 with my friends. Then after a few days, I returned and found that my competition record disappeared from the scoreboard. Someone must press the 'to practice' or 'devirtualize' button. If you press those buttons, the website will ask you if you confirm your action (which is not reversible). Therefore, I pretty sure there is someone who just don't want to see my partipation record on the scoreboard for some reasons that I could never realize.
Just in case some of you don't know (maybe hasn't discovered yet) what the coach mode can do, here are some authority that you can do with a coach mode:
- Read any submission and data (this is well-known);
- Edit TL, ML for any problem;
- Add, delete problems of any contest
- Add, delete teams' participation record, ghosts from the scoreboard
- Rejudge, skip, reject any submission
The Codeforces community is getting larger, and therefore it is getting relatively easier to achieve Master rating (>=2100), which is what I know about getting a coach mode authority (maybe slightly different but generally it is i guess). I think it is about time to restrict the coach mode authority tighter before anything worse happens.
The simplest way is, of course, to limit it by increasing the rating bound(maybe >=2400). But it might be too mean for the community. But at least, I feel it will be more appropiate to let the contest/problem setter has more rights to modify the contest by himself. And I feel it is OK to let the normal coach mode only have the authority to read submissions and data instead of everything. I haven't got time to think about more possible options and I hope we can have some discussions in the comment.
I don't know whether Mike will see this blog so I think I should @MikeMirzayanov here. And I still want to express my gratefulness for building and maintaining such a useful and convenient platform (including Polygon) for all CP participants and problem setters.
UPD1: Some comments say that if you are purple and have done a few contests, you also will get a coach mode authority.
UPD2: Just check another example, in 2021-2022 ICPC, NERC, Southern and Volga Russian Regional Contest, you will see that Team Longest SubRoutine also got removed from the scoreboard for no reason (Confirmed by the team that it is not by their hands). This is truly a disregard to the team's effort and may ruin their training log.
Actually I am not very happy about not seeing any officials including Mike himself to respond this. I feel this is a serious issue at least as important as finding and solving potential hardware issues.