Continuity mistake: When the Boeing 747-200B initially taxis out from the gate, the flaps are set for take-off. After the stairs get hijacked, the remaining shots show the plane with the flaps retracted.
Continuity mistake: In the impound lot scene when Fletcher is talking with his ex-wife next to her jeep the driver side window starts to open. It's closed for most of her close up, then switches back to open when she is getting in the car. (00:37:10 - 00:37:57)
Character mistake: When Dana Appleton objects to Fletcher badgering Kenneth Falk, the judge overrules because Falk is Fletcher's witness. You still aren't allowed to badger your own witness in a trial, which the judge should certainly know.
Continuity mistake: At the end when Audrey is drinking booze during take off, Jerry says "I love you" to her. Her drink instantly empties itself despite being full in the previous shot.
Answer: First of all, she's not "on the hook" anyway...this is a divorce proceeding, not a criminal trial. And second, this film has multiple inaccuracies in its depiction of the legalities involved (see Legal Eagle's two-part analysis on YouTube for a very good rundown); the fact that no-one brings up fraud is the least of them. It's not important to the plot, so it is simply brushed aside, counting on us (the audience) not worrying too much about it, like so many other lapses of reality in comedy movies.