Under federal law, the president cannot turn down Secret Service protection, but he can set limits, such as deciding how close agents can get and whether he will go to places they think are unsafe. If you don't have proximity, you have an open door. . . . Some bad guy is going to walk through that open door. While that may be the consensus view at the Secret Service, it is not universal even among the fraternity. Several other former agents scoff at the notion that presidents would put their lives at risk to cover up criminal conduct.
Presidents ask agents to step aside any time they are too close when they play golf.
The Secret Service was founded in 1865 not for security but to combat counterfeiters rampant in the post-Civil War era. In the years since, it also has been tasked with protecting their families, their vice presidents, their predecessors and would-be successors, and their visiting foreign counterparts. To stay close to those they are guarding, Secret Service agents say they will go to unusual lengths, even disguising themselves to blend into events around them. They have dressed as soldiers, doctors, college professors and construction workers. When a president throws out the first baseball of the season, one of the umpires sometimes is an agent.