Special guest stars, as I may have told you in the past, pose a problem for television shows, particularly whodunits.
If you recognize the actor or actress's face when the police are questioning an individual, you know that the police are going to be revisiting that person later. Faces you and I know don't just randomly appear to be questioned by police in one scene and then passed on, never to be seen again. No, if you know the face, the odds are good that they were involved in a crime (or will soon become involved after the fact). From a storytelling aspect, it's an issue — any surprise or shock is greatly reduced.
Looked at from the opposite end, from the position of the producers, putting a face that we know on television makes us more inclined to either tune in (if we know in advance), or stop our incessant channel-flipping when we spot them. Special guest stars are, in that way, a boon. I hope — I supremely hope — that the producers take into account the problems and not just the benefits when nabbing a special guest star.
Last night's Law & Order featured an appearance by Robert Iler as a "special guest star." Okay, maybe they didn't name him as such, but I'm sure that when people were flipping the channels at 10:08 last night (or thereabouts) they noticed "that kid from The Sopranos, you know, AJ, Tony's son."
Anyone who recognized Iler, even if not by name, knew he was instantly involved, somehow, in one of the criminal activities the cops were going to be investigating that evening. No, he may not be a "big" star, but the odds that he was going to be doing Law & Order solely to be the son of the guy who committed the murder were slim to none.
Consequently, it came as no shock whatsoever to find out that his character was involved in nefarious, illegal activities. I'm just happy that the show didn't wait terribly long to make it clear that he was involved and to have the cops go after him; it would have been a horrible L&O "twist" to have the good guys only figure out in the last 10 seconds of the episode that Iler's character was "the guy."
It seems to me that having Iler's character targeted in the first half of the show was a good way of utilizing the face recognition Iler has and still not trying to portray his character being guilty as the twist. It was actually something of a happy medium, although I do wish they could have gotten there even more early than they did, I think they hit on the character about 20 or 25 minutes into the show, and I would have loved him to have been fingered closer to 12 minutes in. And don't tell me that Law & Order cops never make an arrest that early — they had the first guy in handcuffs at about 13 minutes in last night.
Like I said though, it's a tough problem to try and tackle. If I were grading them, I'd give them a "B" on the way they handled it (and I'm told I'm a harsh grader).