Generally it‘s not easy to tell if someone is using an autoclicker. It’s easier to tell if they are fighting someone on 1.9, because you can clearly hear how their autoclicker maintains the exact same speed with no variation.
It’s a lot harder to tell when they are placing blocks, because the speed is not always the same and there’s always the possibility that they are jitter clicking or doing some other technique.
If you suspect someone of cheating, please report them here (if you play on Bedrock) -
http://cbecrft.net/bedrockreports or here (if you play on Java) -
https://reports.cubecraft.net/ and the staff team will handle your report accordingly. Thanks!