Do not share your seed phrase. Do not! Instead, the xpub should be shared. Download sparrow, create a multi-sig wallet and it will be immediately clear what I'm talking about.
now they have an extra multisig / shared wallet on top of their own solo wallet that they can still control as normal?
Yes, they would have a wallet that's single sig and a wallet that's multi-sig with different Bitcoin addresses. If you download sparrow wallet and create a single sig seed phrase for one script type and then create a new wallet, import the seed phrase and use the multi-sig script type, you will see different Bitcoin addresses and see what I'm talking about.
Do not share your seed phrase. Do not! Instead, the xpub should be shared. Download sparrow, create a multi-sig wallet and it will be immediately clear what I'm talking about.
Yes, they would have a wallet that's single sig and a wallet that's multi-sig with different Bitcoin addresses. If you download sparrow wallet and create a single sig seed phrase for one script type and then create a new wallet, import the seed phrase and use the multi-sig script type, you will see different Bitcoin addresses and see what I'm talking about.