The freeze address or UTXO is on the software level, so if you have installed electrum on your device then it only works on a particular level but if you import the same wallet into a different device then you need to freeze the address or UTXO to make it unspendable on the device again. So yes, it's not possible for anyone to restrict an incoming TX to an address.
Exactly importing the seed phrase in another wallet doesn’t mean that the freeze addresses or UTXO will be there too, but that is not related to importing the wallet using the file document because one thing the file document does is that it actually contains all scripts and commands previously setup like the Freeze coins and even the password to that wallet.
Why someone would freeze an unused address? You freeze addresses containing funds or eventually emptied ones that have been used for a transaction that you don't want to be linked to your wallet. So yes maybe if you try to freeze some addresses that have never been used before you will see them appearing when you do a receiving address request, or for the change but nobody does that in reality, since it's useless.
Both of you are saying same thing there is no reason to freeze up and unused address as it can still be available for both recipient or as change, the only reason I see that the unused address can be frozen forehand is when you’re expecting some funds on it and do not want it mixed up with others later, maybe funds from somewhere you don’t trust and don’t want it mixed up. This too is only possible if you’re not gonna request a change or receiving address before the funds arrive