It's trivial to detect an alternate profile without access to developer options and the main ADB shell. It will be detected as part of standard forensic data extraction. Wiping secondary profiles can be easily detected too. Everyone is going to know the feature exists if it's broadly deployed. A deniability feature would need to be set up very differently to what people think it should be like. With GrapheneOS being able to run and use Virtual machines, we'd want to work on a feature where there is a virtualized GrapheneOS in the future where it could be set up like this.