Sharing ownership of coins via Multi-Signature transactions I wonder if it would be possible to use a script to share ownership of an UTXO between 2 or more people.


1 &lt;A pubkey 1&gt; &lt;B pubkey 2&gt; N OP_CHECKMULTISIG


That would let every owner be able to spend these coins without needing to ask the other ones for permission.

This is at the moment a valid standard script that is accepted when it is being sent to the Bitcoin network. 

But i am asking myself if this could be used to trick people? 

If i pay with such a transaction with the receivers public key and my one in the script, i would still be able to spend these coins afterwards. And the receiver would not even notice that i am able to steal back my paid coins. Is this a realistic scenario?
Generally wallets don't recognize payments to random outputs, even if they're able to spend from them. In situations where multi-signature outputs are used, they're generally part of a scheme that the wallet knows about and participates in (for example 2-of-3 multisignatures where one of the keys is in your phone, one in a vault, and one is held by the wallet provider; usually the provider signs transactions you ask them to, but you can also spend with just the vault key).

This avoids the situation you're describing.