The New York Times writes:
Donald J. Trump is preparing to walk into a Manhattan courtroom as both a defendant and a candidate, making final plans for his arrest on Tuesday [...].
Why would he be arrested? Is there a danger of flight? That seems implausible, given that he has arranged his appearance in front of the court out of his own volition, and because of his commercial, family and real estate ties to the country, and his plans to run for president again.
Is there a danger of destroying evidence? In all reality, that would have happened by now, and most relevant searches have probably been conducted already.
What other reasons would be there for an arrest?
As a clarification: If I'm not mistaken, in Germany an indictment would simply be delivered by special registered mail, unless one of the above-mentioned dangers was present.
In the U.S., a simple delivery of an indictment can take on an appearance which I can only perceive as unnecessarily disparaging. A defendant is presumed innocent unless proven guilty. To me this principle implies that defendants should be treated with respect like any other citizen. Putting them in humiliating situations, let alone using force like restraining them with handcuffs like in the case of Mr. Weisselberg contradicts this principle, unless there is reason to believe they would flee or otherwise obstruct the trial.