Read more about the scam here:
[Warning] Trust wallet tron multi signature scam.
Bitcoin multisig wallet is different from how Tron multisig wallet works. The scammer is using Tron multisig wallet to elicit the scam because out of the two private key or seed phrase, there is only one (private key or seed phrase) that is able to access the wallet, that one remain known to the scammer. The other private key or seed phrase can only be used as watch-only, it can not be used to spend the coin, the scammer will give the second private key or seed phrase to the victim, which the victim can not spend from.
The victim will think he can send Tron to the wallet to withdraw the USDT, but not knowing he has the private key or the seed phrase that is only used for the purpose of watch-only and can not be able to spend the coin.
I do not like Tron for that, many people can fall being scammed because of how the Tron multisig wallet is.