TxRhino and Shrekney are right - my husband's former attorney told us he would be indicted by x day - and about 10 days later, when he really was indicted, the FBI and security guard from Union Pacific showed up around 9:00 in the morning with the paperwork. The FBI agent, being a real smarta** asked if hubby remembered him and shoved the indictment at him, told him to show up at the Fed. Courthouse on a certain day, then very snidely told him if he couldn't get himself there, he'd give him a ride wearing pretty silver bracelets (yep, those were his words... this guy is a real piece of work).
If you are going to retain private defense counsel, that attorney can meet with the US Attorney's office and negotiate the next steps. Depending on the outcome of the meeting, you may never get arrested. I have had clients whose attorneys arrange for them to appear at the magistrates court for arraignment, the first plea and bond, then go to the Marshal's Office and pre-trial services and home. The pre-arranged process takes about 3 - 5 hours. Occasionally, the agreement is not followed, and they pick the person up. I think desire for publicity is ususally the reason.
Since the Federal Defender doesn't get involved until a charge is made and the Judge appoints them as counsel, I don't think they have the same option.
And in my case, the secret service called me and told me they issued a warrant for my arrest as there was an indictment. I was able to go to the arraignment, "check in" with the Marshall's office and went home
I found out at 5:00 am when the Feds kicked my door in and informed me. I knew it was coming for about 3 months previous to that because all my cohorts had been indicted, it was only a matter of time cause "loose lips sink ships." Looking back it wasn't that bad of an experience but Mexico is beautiful year round I hear!!