Wet application for vinyl window stickers or adhesive-free cling materials is sometimes used for easy positioning on very high-energy surfaces. The high surface energy makes the sticker material have a very high initial tack. Making it very difficult to lift up your print and reapply if you encounter air bubbles, or realize it’s improperly aligned.
This method is not always necessary, and most of the time a dry install is recommended. If this method is used it is most commonly used with vinyl sticker prints on storefront windows, and adhesive-free clings.