In the wake of a tragic and unprecedented shooting at a late-night Thursday showing of “The Dark Knight Rises” in Aurora, Colo., the entertainment industry is beside itself in mourning and the usual importance of B.O. numbers is being set aside. Warner Bros. announced late Friday that it would not be reporting grosses out of the respect for the victims, and so far Disney, Fox, Sony, Lionsgate and Universal have followed suit in solidarity.That said, estimates from rival studios put the pic at around $75 million domestically from Friday, the third highest opening day in B.O. history after “Harry Potter and the Deathly Hallows: Part 2″ ($91.1 million) and “The Avengers” ($80.8 million). Though it’s too soon to say what, if any, effect the shooting will have on “TDKR’s” weekend haul, it has prompted exhibs to beef up security at screenings of the film to prevent copycat attacks, and prompted WB to cancel the film’s Paris premiere with the likely cancellation of the rest of the pic’s int’l press tour. The tragedy won’t keep “TDKR” from a boffo bow, but it may make distributors and parents wary of similar late night showings of films going forward. “I do think the overall business was affected,” said one studio distribution executive. All said, early estimates peg the pic at north of $170 million in its first three days, the second highest Stateside bow of all time after Disney-Marvel’s “The Avengers” at $200 million. In 2008, “The Dark Knight” experienced a Friday-to-Saturday drop of 30% and a Saturday-to-Sunday drop of 35%. “TDKR” should follow a similar trajectory, but its fall off may not be as steep as early breaking news of the shooting will likely drive would-be Friday night moviegoing traffic to Saturday and Sunday screenings instead. Most exhibs have announced they will honor refunds of preordered tickets, facilitating the showtime switch for fans. However, a larger midnight gross at $30.6 million to “Dark Knight’s” $18.4 million may actually create steeper drop off due to front-loaded interest.