I have used Dow/Scrubbing Bubbles spray cleaner for years & never wet the surfaces first, & the label does not say to do so. I would think the cleansing action would be diluted.

P.S. However, I would not wait for a surface to dry before applying the cleaner; I might just use a little more of it.

I like to apply Scrubbing Bubbles spray when my bathtub is still wet after I shower. The spray mixes with the film of water in the tub and it seems to work better. Yes, it's diluted but a little cleaner goes a long way. When I use it to clean tile walls, sinks, etc, I spray it on dry. But I seem to use more. Take Kathleen's advice, both ways work.

The problem I have with applying products to dry surfaces is that they tend to dry out during the 5 or 10 minute waiting period recommended on the bottle.

I think I'll try a combination of all of the advice! I've got a small stall shower to experiment on. I'll let you know how it goes :)