I can tell you with some authority. Not because I'm good, because I was lazy. LOL! What should have been done during season, has been done at the last minute. Sometimes when hunting a new spot, trimming is necessary anyway. I've cut lanes right in the hunting season and have seen big buck droppings the next day right in the shooting lane. I've also done numerous trimmings to get me a shot or better view of an area and have seen deer move through the area right away. I also try and be quiet doing it and get it done as quick as I can. I mainly use hand pruners, loppers, a pole-saw... and sometimes have used a machete with my custom sharpening job to cut tall grass.
Most activity you do in the woods, if the deer see you, hear you or smell you, then that's that, but it doesn't mean they'll leave the area and your hunts will be ruined.
I also only cut during the middle part of the day... around 11:30am to 3:30pm to keep from scaring deer that are already on their feet. Plus any residual odor is slightly dissipated which may help me hide my presence. Don't know how much ground scent I leave, but regardless, I'm seeing deer right away.
If you have to, do it in the middle of the day, be quiet and get it done quickly if at all possible. Trimming and leaving ground scent is about as much disturbance a hunter can leave, so it's not normal, but has to be done sometimes.
Good luck,
iSnipe