Depends on who you are calling ‘they’.
When a ship transits the canal, it doesnt do so on its own power. The Canal Authority (Egypt) has tugs come alongside and the tugs guide the ship through. The almost certainly send a pilot to the bridge of the transiting ship who coordinates ship steering with tug operation. This is very similar to harbor ops throughout the world.
The Egyptians make ALOT of money with what they charge for transit, so they have little incentive to block the canal.
As an aside, our carrier group transited the canal 6 times in the lead up to the up to Desert Storm. It takes about 12 hours to go through the canal. From the deck it is pretty boring scenery but its was interesting to see the occasion tank hulk (Arab) on the banks; remnants, well preserved in the desert environment, left over from the 67 war.
tank hulk (Arab) on the banks; remnants, well preserved in the desert environment, left over from the 67 war