Sometimes you will & sometimes you might not ... there's just no clear, rock solid answer to that question.
I've seen people drive a pontoon or boat right into a stand of timber, run into the tree and then tie up and start fishing ... and actually catch some fish. I've also seen videos of schools of fish move away from a boat at the same speed that the boat is approaching them (Livescope videos). I've also fished in a boat with Livescope, ran over the brushpile with the trolling motor, backwashed the brushpile putting the trolling motor in reverse to get back into casting position & still catch fish off of it (not to mention getting hung up & breaking off in it). Had the same guy that I fished with, with the Livescope, tell me that on another lake (with clearer water) that he's seen big schools of fish that would not touch a bait if the boat was any closer than 20ft from them ... then back off and catch fish. On both of these lakes it's not out of the question that idling boats, or those running WOT, run right over those same submerged brushpiles/trees.
Of course I'd expect a big motor to scare the fish off brush that was in fairly shallow water, but give them 10-15fow & brush to hide in and it may not run them off.