Mark Brader:
If you go to a baseball game and it's canceled due to weather, you
turn in your ticket stub for compensation in the form of admission
to a future game. ...and is called a raincheck.

Erick Barkhuis:
...which fits very well with the North-American expression "I don't
know exactly, but my ballpark guess would be..."

[referring to spectators, who couldn't really tell whether a runner was
out or not, but at the same time boo the umpire because the call went
against their own guess...]

Ah, sorry, no. It means a guess that you don't expect is right, but you
do know it won't be terribly wrong. It will be "in the right ballpark"
(that's another common expression) -- a ballpark being a fairly large but
still limited area. Ballpark guesses are made on numerical questions,
not questions like whether a runner was out.

If you ask me how far it is from here to Paris (bringing the thread back
to European travel), and all I know is that it's more than 2,500 miles
and less than 7,000, then I might say "I'll make a ballpark guess of
5,000 miles."
--
Mark Brader, Toronto | Bad news disturbs his game; so does good; so
| also does the absence of news. --Stephen Leacock

My text in this article is in the public domain.