Here's problems that happen on illegal copies of Theory games or spin-offs that you wouldn't find on legal ones.
Supernanny: Theory of Nicole ~ Crashes on title screen if pirated
Supernanny: Theory 2 ~ Does not start up
Supernanny: The Theory International ~ Before the game's intro, the screen will display a globe of the Earth shattered in pieces with a message reading "Warning: This game is pirated! Now where's the swashbucklers when you need 'em?" The player will hear one of the Canoe Killers (presumably Dead-Eye Dennis) impersonating a pirate reading the message.
Supernanny: The Theory 8 ~ In Japan, Tellyznphonezfor Adultsonly will shout to the player in English, and all the language is uncensored. He will shout "YOU'RE A B****** B****, AND I'M TALKING TO ZE VHOLE EVERYBODY YOU MET, NOT JUST YOU, AND SPEAK ZENGLISH!!!!!!!!" After that, a creepy face even creepier than Regan MacNeil appears.
Sophie the Otter: Tough Girl ~ A Japanese child's voice, possibly Toshio Samo's says "Pirate! Pirate! Pirate!" in Japanese in a loop until the final boss, where the game will crash with a black screen.
Reicheru the Yokai Spirit: Abusive Fall, Concerned Rise ~ Game freezes with an error message of Reicheru's corpse.
Another vs. Normal Party ~ Hangs at title screen (on 3DS) or freezes when appeasing Another Kazuki (PC) due to the bugs.
Kodomo no Kara Sasayaki: Evil Whisper ~ Locks up with an image of Toshio's Shadow plush, with its stuffing on its torso, viewed from the side, as it was disembowled, with the message "This game seems to be an illegal copy" in Japanese.
Gemma's Super Fun Game ~ Crashes before the first cutscene plays.
Another vs. Normal Party: iNSaNiTY ~ Locks up on a Chibi image of Ryo, Shikoki, and Satoshi Jr. With a message in Japanese saying "Thanks for playing!", these kinds of messages are on the sequels of this game.
Another vs. Normal Party: Supernatural Spirits ~ Same as prequel, except with the Sly Fox Trio. The message is in German and it reads "Thanks for playing! Now get out and have a nice day!"
Theory World: Moonshine and Sunlight ~ In Moonshine, Shirtless picture of Another Giuseppe Todaro, who is winking and is holding a can is spray paint on a street, the message translated from Italian is "Too bad, huh?" In Sunlight, Another Reicheru, the message says "Nope, not this one." with a small smirk, in a classroom.
Theory World 2: Alpha and Beta ~ In Alpha, we see a picture of Aristotle Marx chasing Marilou the Otter (who is holding her Shy Violet from Rainbow Brite doll). In Beta, Toshio Samo is chased by Aristotle instead. In Alpha, Aristotle says "Piracy makes otters cry and so do video games!", while in Beta, he says "The Japanese should not buy pirated games! Why? Because all video games shall turn them into vampires!" In both versions, we hear Aristotle laughing in a sinister voice after his quote.
Supernanny: Theory Smash Brawl ~ We see five separate squares displaying the Freak Foor logo, followed by the game crashing.
Theory World 3: Lesser and Greater: In Lesser, Marie Lara-Rutter is backed by a North Korean flag and is wearing a pirate hat, she politely tells the user to buy a copy of this game, in Greater, Marie's friend Andrew is backed by a South Korean flag and is wearing a pirate hat, like Marie, he politely informs the player to buy a real copy of the game.
Another vs. Normal Party: INHUMANITY: If the game fails a copy protection checksum and thinks it is used on an emulator, the message "F*** YOU EMULATOR!" with Huizong Zhungxi, if the game is illegally copied, the game will freeze after appeasing Huizong.
Supernanny: Death Combat: Enemies are invincible and guns shoot out dead cats. This is one of the more benign Anti-Piracy measures.
Supernanny: Battle Royale: The game freezes after selecting any mode. Upon freezing, a picture of a gun stuck to the ground will show up with the words "Oh look! You just bought a pirated copy! Congratulations, you get nothing!"