Liquid damage in electronics is a bit like pancake batter on the counter: on Sunday morning, it's relatively easy to wipe off. Dried pancake batter on Sunday night—that's a different story. The same thing happens with water/liquid damage.
When we put a phone in rice, it is the same thing as doing nothing. It just FEELS like we're actively trying something. Corrosion is instant when a phone hits water. Sometimes the corrosion hits important components, sometimes not. If we resist turning the phone on until it dries on the counter, in the rice bag, or anywhere else, sometimes we get lucky. If we had the phone in the rice bag, we think the rice saved the phone. But it didn't! Even if the phone seems to be working, it will have oxidized solder joints that are weakened and brittle. Corrosion will continue to spread inside the phone. We have done nothing but experienced temporary luck.
The real secret to water damage? You don't want to dry it!
What you want to do is first displace the water—or more specifically, all the conductive stuff in the water. You can do this best by using 90%+ isopropyl (rubbing) alcohol and a toothbrush. Open your device as soon as you can, take out the battery, and get scrubbing. Submerge the whole motherboard in alcohol, and scrub away. Only then, dry it and see where you stand. By getting the liquid displaced before it can dry, we are cleaning the pancake batter on Sunday morning. This is your best strategy for liquid damage.
Of course, it's tempting to just put the phone in rice—you never know, it might be okay. We want to ignore all that work above and just hope for the best instead.
You'd be hard pressed to find any experienced professional in the repair industry that doesn't roll their eyes when they hear the word "rice." We see the sad result of phones/devices that have been carefully placed in the Mahatma bag with fingers crossed.
To all repair professionals out there: please join in sharing some pictures of what a phone/device really looks like inside when we open it up after its romp in the rice. A picture is worth a thousand words. Maybe it will help show folks the reality of the role of rice in water damage.