[CecilOne]

I found this in the NCAA Umpires Manual:

"Tips on Interference
• To have interference, there must be a possible play.
• The three foot lane keeps the game even. Do not confuse an overthrow with a bad throw.
• If a runner is coming toward a defensive player a throw is not required to have an interference
call.
• If a runner is going away from a defensive player there must be a throw before interference
can be called"

and

"A wreck usually requires no call or signal. If a wreck looks like interference or looks like
obstruction but in your judgment it was neither, then signal Safe and continue with your duties on the play.
By signaling Safe, you tell the teams that you have seen the action, you have made a judgment on the action, and you have determined that no violation occurred. Be prepared, at the end of playing action, to explain your judgment."