I'm sure that the traffic in that area must be harrowing for submarines. A submarine came way to close to my boat in the Strait of Juan de Fuca one day. For a while, I thought that a buoy was following us somehow, until I realized that a sub was just beneath the surface. It surfaced as it came on to our beam. I cannot remember how long my heart rate took to get back to normal. We were not near their port or in any restricted waters!
I seriously doubt that the carrier groups hang around the horn at Hormuz. We have really generous support facilities some of the Gulf states. Abu Dhabi, IIRC, can even accomodate docking a carrier.
I'm not so concerned about when they "hang around" the straights but with the fact that they have to transit the Straights on entering and leaving the Gulf. Those transits are very predictable and obvious Also the super tankers that are perceived as our Achilles heel in this area must make that same transit, so it is a rather obvious target for our enemies.
What concerns me is what is possible, from their point of view. Not likely. Not logical (from our viewpoint). But only what is possible.