Continuity mistake: The poster that Tiana has that her father wrote on says "Tiana's Place." When she finally gets her restaurant, the name is "Tiana's Palace" yet the menus still say "Tiana's Place." (01:29:00 - 01:30:00)
Continuity mistake: Near the end, Dr. Facilier has Tiana pinned down with his staff. After Tiana uses her tongue to grab the talisman from Facilier's hand, the staff is no longer anywhere to be seen.
Continuity mistake: Tiana wears a pair of gold earrings during Charlotte's ball. They disappear when she's watching Charlotte dance with the prince and reappear later. (00:23:55)
Continuity mistake: As Tiana and Naveen are floating over the swamp hanging onto the balloons, the amount of balloon strings alternates between three and four stings depending on the angle. Most of the time, when the shot is on Tiana there are three strings and when on Naveen there are four. (00:33:00)
Continuity mistake: Hoping to turn Naveen from a frog back into a human, Charlotte kisses him seven times, leaving seven sets of lip prints around his mouth. He remains a frog, but in the next shot, all the lip prints have suddenly vanished.
Continuity mistake: When Lawrence finds Naveen playing with the local jazz band, we see three young girls standing together on the left. Then a few shots later, two are standing together with a different lady who switched places with the third young lady (the different lady is tall and has weird looking feet).
Continuity mistake: Tiana and Naveen have been turned into frogs. They go to see Mama Odie, hoping she can turn them back into humans. She holds out a giant pearl and the frogs are reflected on the surface, but in the reflection the frogs have switched positions.
Continuity mistake: When Tiana is told she was outbid, the real-estate agent in the head of the horse costume turns her through the middle of the two parts of the horse costume. A few seconds later you see the two agents get back in their costume and walk off seamlessly.
Continuity mistake: When Dr. Facilier transforms Tiana back into a human to offer his deal, she is wearing a white dress with a large feather boa around her arms. When Tiana turns to the ukulele player whom she thinks is Naveen, the feather boa falls off her and is never seen again during the rest of her temptation.
Answer: They physically left. Just because we didn't see it happen doesn't mean it didn't happen. It's a montage of their activities after they returned to human form.
LorgSkyegon
I thought as much, but it would have been even better to see a montage of them physically leaving the bayou and planning their church wedding.