In the lead up to the American Revolution, the sedition charge against John Peter Zenger and multiple cases of import tax offenses were thwarted by grand juries. Jurors declined to let cases go forward to trial as the underlying laws were unjust. The Founders saw the value of grand-jury review as a restraint on unreasonable Government power.
Pure bypass of the federal grand jury requirement not yet been necessary. This is because “contemporary practice”, as with most of the Constitution, has diluted the traditional significance of grand juries in protecting the accused.
First, the Grand Jury Requirement Clause is not "incorporated" against the states. Second, courts have blocked challenges to federal grand-jury secret procedures. Third, courts do not required prosecutors to disclose evidence to the grand jurors that is favorable to the accused. Forth, prosecutors can obtain an indictment by presenting nothing but hearsay, none of which will be admissible in a later trial. Fifth, highly trained prosecutors and exceedingly complex federal criminal law leave grand jurors almost incompetent to answer the question: Is there enough evidence? Today, grand jurors follow prosecutor advice and yield a true bill in virtually every case.

Since 21st century Federal Grand Juries have devolved into accusatory mechanisms of the state. Perhaps the only visible protection afforded by the right to a Grand Jury is one seen from a throughput perspective. The rate at which the Federal Government could produce scurrilous charges against citizens is somewhat constrained. The capability of Grand Jurors to frustrate widespread prosecutions of future intolerable acts remains to be seen.