IT'S NOT A MINHAG

 

Parshas Hashavua שופטים תמים תהיה עם ה' אלהיך דברים יח:יג      IT'S NOT A MINHAG & IF YOU TRUST IN HASHEM, DON'T BOTHER DOING IT  The Sefer שלחן העזר quotes the ספר המטעמים*  "חתנים & כלות before walking down to the חופה untie all the knots they are wearing.  The reason for doing so is to prevent from כשפים (witchcraft) which might put a spell on the couple and prevent them from having relations." Untying the knots is not a Minhag but a סגולה people adopted to prevent witchcraft from harming them. The יראים & תמימים (who fear & trust Hashem) rely on  תמים תהי' עם ה' אלוקך  & שומר מצוה לא ידע דבר רע (Don't bother untying)" * Probably the first & original source for this non Minhag practice