This type of mistake happen because of pronunciation. Here one hotel in is opened. Owner painted name in Punjabi and Hindi. Name of Hotel is Prasadam. But when we write it in Punjabi, we pronounced it Parsanda. They also painted in Hindi Parsadan.
Some times mistakes are deliberate just to attract people. Once a businessman hung his banner upside down. More people were attracted and his advertisement was successful.
I agree. The purpose of committing mistakes deliberately on the display boards and banners is to draw the attention of the public. In this process, laughter generates. A display board on a Hair cutting saloon announces, "We cut the children too here."