You bring up an important point-
apparently Mara Lago is HEAVILY guarded by on grounds security too- was the FBI hoping that the security would not know they were fbi because of lack of identifying markings and try to detain them, causing a possible incident for the use of deadly force?
The FBI coordinated with the Secret Service prior to their arrival to serve the search warrant and the Secret Service facilitated the search. Trump was not at Mar a Lago when the search was conducted, because, as everyone knows, Mar A Lago is closed from May until the fall, and Trump moves to New Jersey. The FBI was dressed in casual wear to try not to alert the public. The only reason this search became public knowledge was that Trump tweeted or truths or whatever about it. Everyone should just calm down. This is just silly.