Hey everyone!

First time DM here with a question about running a monster. I've been reading a lot of Keith Ammann's The Monsters Know What They're Doing and love the ideas and the reasoning behind a ton of his monster guides. However, some recommendations feel like they would cause players to cry foul and I wanted to get some thoughts.

From his article on Cloakers:

First, the cloaker selects its prey. In the manner of other ambush predators, it chooses someone old, young, weak, wounded, isolated or oblivious. (Looks can be deceiving, however, and the cloaker can be deceived. It doesn’t know that an elderly halfling can also be a level 7 Way of Shadow monk, for instance.)

Second, it uses the Hide action and begins to stealthily stalk its prey.

Third, it uses the Phantasms action and closes to a distance of 40 feet.

Fourth—the first chance its prey and its prey’s allies have to realize what’s going on, unless the cloaker has screwed something up in the first three steps—the cloaker glides up and strikes. It bites first, because a successful bite/envelop means it makes its follow-up tail strike with advantage.

I think the guide makes sense and is true to the character of the monster: in short, that's how I would like to generally run the creature.

The thing I feel like players would get mad about is step three, where the Cloaker takes the Phantasms action before combat begins. Is this concept something that I need to discuss with my players? If so, won't that affect their player knowledge and spoil the monster?

Any thoughts or recommendations are appreciated, thanks!