A certain company or companies that specialize in transformation technology create a Fair each and every year. At these Fairs all sorts of attractions and gadgets become available to try out and purchase. That said after the first few years the Fair started evolving into something other than a tech show and got special rides and attractions created by professionals who used the technology from previous events to create amazing shows and gadgets. For example a mechanic who worked in a club saw some special lights which changed people depending on the color of the light and decided to create something out of them. After a little fiddling around he created a disco ball which shined transformation light everywhere making an interesting transformation dance floor which soon became popular. The guy now runs a special area to show off his new disco balls. Course there were several other inventions that were added to the fair ranging from special food to entire cities based around transformation.
Now there are so many inventions that it would be hard to track everyone's transformations. To combat this and to heighten public decency in the Fair everyone attending must change into a special stretchy skin tight suit which will cover any body type. Said suits come with a special chip inside which acts as identification. Once a person changes into a suit their appearance and details are put into a computer so when they leave the fair they will be able to turn back into their regular selves whether they want to or not. After all the fair was made to show off the technologies, not give away free transformations.