Reasonable? Given that "deadlines" to register by are often well in advance of most tourneys, I'd say 1 week prior to game 1 is reasonable.
But having a kid play travel ball since age 8, I know "reasonable" is almost exclusively a pipe dream.
I'd consider 90%+ of the schedules I've gotten over the years to come at times that I'D consider to be rude and inconsiderate. But also par for the course. Given that tourneys exist solely to make money, late additions to the field will almost always be accepted and with them, necessary logistical changes. We're all trapped rats and the tourneys know and exploit that whenever it'll benefit them.