Blocking out of bounds?

[JugglingReferee]

Originally posted by w_sohl
B1 blocks A1 knocking him out of bounds (Still on his feet), B1 follows and continues to block A1 out of bounds.

Is this legal or would you flag for Illegal Personal Contact or possibly another penalty?

A can come back in without penalty, but must attempt to come in right away.

B leaving the field on his own is a foul if he further participates, including continuing to block A.