My opinion is......
Better to have a well packed, safely attached reserve (check the handle and pins are attached correctly before each flight) and not use it, than not have one.
Who knows what can happen up there, not clipped into carabineer correctly, carabineer snaps (not going to happen but you might have damaged it on the ground). Helicopter flys too close, collision, swing arm failure. Stuck in a spiral. Prop spins off and rips wing or lines. Brake handle wraps into prop.
Does'nt matter how nice the conditions are!
Yes many of the above are very unlikely but still possible.
Who knows when you might need a reserve?
Mike