One of my party members was recently in a bar fight and to help him out a bit I used my Wild Magic Sorcerer's "Bend Luck" ability to give his opponent a penalty on one of his attacks. This penalty made sure that the attack missed my friend.
The way we role-played this is that my magic loosened up one of the floorboards the enemy stepped on while attacking, which made him lose his balance and miss the attack.
My question is: Could this manipulation be detected by anyone? Normally in a fight with monsters it doesn't matter but in this situation there were spectators shouting around them and placing bets so I would guess they would not like someone manipulating the fight. The ability doesn't specify this and I would like to know how others would rule this.
My DM ruled that if I could find a way to make the environment work against my target it couldn't be detected by anyone looking for foul play.