Take a signed card (signed and folded by the spectator) and let the spectator also sign any wine glass. Cover the signed glass with a borrowed silk or hanky and link the signed card on the stem! You could even rotate the card on the glass while the spector see his own signature! You reverse the action and unlink the signed card from the glass and hand out the glass and the card as a souvenir!
No hidden cuts, no glue on the card, no magnets and no thread. Use any wine glass! Make the gimmick in about 3 minutes! Very easy to do!