No, slight touch would result in the noise decreasing.. you were not in TS to witness the noise it actually makes. They thought I was at Heathrow 
Well, a couple of blades being removed would:
1. Put the fan out of balance, resulting in noise.
2. Result in less air resistance, hence a higher fan speed.
Pushing the fan whilst its moving increases the resistance, so the fan slows down. Touching the fan may also reduce the vibration (being off balance) because it's dampened against your finger.