Some scammers use scripts to lag the game during a trade, making it impossible for you to click "Unaccept" before they remove their pets.
Some developers use obfuscation (making code unreadable) or "anti-copy" scripts. However, these are often considered "security through obscurity" and can sometimes be bypassed by determined exploiters. For Players: Preventing Pet Theft Pet Simulator X - Anti Steal Download
There have been reported exploits where hackers could steal pets currently equipped by players in public servers. To stay safe, many players recommend using private servers or not equipping your most valuable pets in crowded public areas. Verification & Safety Warning Some scammers use scripts to lag the game
Never invite strangers to your bank. Hackers have historically used bank exploits to steal IDs and rejoin to take items. Pet Simulator X - Anti Steal Download