The short answer is no, if Alice sends money to an address where Bob has a key, Bob can lock her money up forever and there's nothing she can do to prevent that, even if Alice *also* has a key. The long answer is, ok there is something Alice can do to prevent Bob from locking up her money forever, it involves commitment transactions and it's complicated and not a built in feature of bitpac yet.

Alice can commit to msig of Bob & Alice with a especial tx where Alice sign her input of 1 btc and a output of 2 btc , that way after Bob can commit the other bitcoin left and broadcast the tx