Doesn’t matter. If there’s truly no way to verify, there’s nothing they can do in a scalable way to determine people are lying about their main accounts.
The only thing they can do is use fear to get you to comply, or make you doubt your deniable encryption scheme is truly secure.
If they really wanted to could they find out? Perhaps. Maybe if they use CCTV footage and extract your phones screen and do comparisons or something. If you are an individual though who has done something to warrant that level of scrutiny, perhaps the additional crime of lying to a Fed isn’t a big deal compared to whatever crime you have done.
> Doesn’t matter. If there’s truly no way to verify, there’s nothing they can do in a scalable way to determine people are lying about their main accounts.
It doesn't have to be scalable; border control already isn't scalable and relies on uniformed officers making decisions on the spot. It's not hard to add additional point in training that says, "if a person has suspiciously empty phone and the phone is a model X, ask them to unlock the second account; if they refuse or pretend they don't have one, apply 3-30 hours of pressure". This would probably cover 99% of cases.
The only thing they can do is use fear to get you to comply, or make you doubt your deniable encryption scheme is truly secure.
If they really wanted to could they find out? Perhaps. Maybe if they use CCTV footage and extract your phones screen and do comparisons or something. If you are an individual though who has done something to warrant that level of scrutiny, perhaps the additional crime of lying to a Fed isn’t a big deal compared to whatever crime you have done.