In fact the rules of the game - although there is certainly no law - is that you make money available to get all of the staff back to their home bases. A 23-year-old press wrangler was probably making about $2,500 a month for the previous six months and left a job on the Hill or K Street to join the campaign may not have the credit limit on his VISA to front the cost of a plane ticket.
It would not go down well for word to go forth that a presidential candidate or manager of that candidate's campaigns didn't help the campaign kids get home.
The in-state staff and volunteers know the date of the election or caucuses and as long as they hadn't tried to convince themselves that they, among the entire staff, were going to be asked to stay with the campaign, they will have made appropriate post-election plans.
But, for the next 30 years they will be able to tell the story about the night they ran into David Gregory or Sean Hannity at the 801 Steakhouse.
Some staffers do hook up with another campaign. The most often quoted example is Ari Fleisher who left a senior Hill job - communications director for the House Ways & Means Committee, if I remember correctly.
Fleischer joined the campaign of Elizabeth Dole as the senior press guy in the 2000 cycle . When the Dole campaign folded George W. Bush snapped him up to do media for him and he ended up as White House Press Secretary.
Which points out the best advice I give to young people wanting to get into politics: There are a lot of reasons why a campaign wins or loses. It is not likely to be your fault either way. Professionals will not care as much about the success of failure of the campaign you worked on; what they will be interested in knowing is how well you did your job within that campaign.
That's when you get invited to join the circus as it pulls up stakes and moves on.