Who breaks the line? The person who gives bribery or who takes it? First they just want to make life easy. And bribery acceptors who are they? Usually they take position that gives them enough money for living. And as a fact they don't need it.
For example, a construction company may bribe a civil servant to award a contract, a motorist may bribe a police officer not to issue a ticket for speeding, a citizen seeking paperwork or utility line connections may bribe a functionary for faster service, or a narcotics smuggler may bribe a judge to lessen criminal penalties etc. This is a common thing routinely in social life; medicine, government, media, show business, politics, education and others.
All suborders are the same: they usually put, some quantity of cash into the letter. They never send a wad of dollars as a gift! So why would you proffer them as a bribe?
The other side is the not cash bribe. It carries no risk of offense. This could be present that is given just from