Fed: 0 players from team B on field

[Robert Goodman]

This comes from a thread at Coach Huey's.

Time expires for a game on a down ending with a fair catch, and the team that made the fair catch, trailing by 2 points, extends the game for a free kick down. No time out is called by either team. Team B, seeing that nothing their players could do on the field could improve their chances, but that possibly a player on the field could commit a foul, withdraws all their players to the bench.

Is team B allowed to "play" with no players on the field? Or is this failure to be ready to play, and delay of game? Is team A allowed to play with just 1 player on the field?