Not all that difficult, actually

The fact of an accusation is, by itself, enough to scare off prospective employers. The actual facts of the case are immaterial.

There have been a couple of high-profile cases recently where the falsely accused teacher-coach has successfully sued the parents of the accusing teen-aged girl because the teachers were unable to get another teaching job due to the notariety of the case, not the facts. Neither of the teachers that I am thinking of even went to trial - the charges were dropped when the accusers recanted their original stories - but the damage was done. In these two cases specifically, the girls simply were mad at the teachers and they ruined the careers of two upstanding young men.

I'm not naive enough to think that all cases are the same. I'm certain that there are examples of cases that are dropped where the coach is guilty as hell and the accusers just don't want to go through it or are bought-off.

It's just unfortunate that "innocent until proven guilty" is pretty much ignored in these types of cases.