Get the call right? Stray from your primary? How far?

[rfp]

I'm lead, offensive team has ball in the corner right in front of me. Player A1 passes the ball to A2 near midcourt. Player A2 has run a backdoor causing ball to go backcourt. Player A3 clearly retrieves it in the backcourt. No whistle from my partner and no eye contact to me looking for help. Do you, as trail, make the backcourt call? I guess this falls in the category of get the call right and stray from your primary only when it's obvious, but also how far out of your primary do you stray with a weak partner vs. letting/forcing him to get the call right or deal with the consequences? What if it were slightly less obvious and you thought there was a slight chance a defender might have touched the ball before it went backcourt?

Now the game was a blowout and the violating team was on the losing end, so it was easy for me (and everyone else) to ignore, but it got me thinking about the situation if the game had been tighter. Your thoughts?