So I tried my luck and sent an email to gaben's famous email, but figured I'd share here in case people liked or wanted to improve on the idea... So ad-hoc Wi-Fi.

What if the Steam deck had ad-hoc LAN mode:
You meet up with some friends, but don't have Wi-Fi available, so you switch to the Ad-hoc local LAN mode and connect directly between Steam decks to play. You don't need to share a Wi-Fi source, potentially a Steam deck could host the game, and everyone could join in.

Now what if it also had a "Local Player Finder" too?
So for this, of course you would want privacy options, so consider the functionality of Airdrop on iPhones as an example. You can enable or disable visibility, as well as limiting to friends, etc.
Now moving to functionality.. You're on a 4 hour plane/train/bus ride and you have a lot of time to kill. You have the local player finder enabled and suddenly you see two other Steam deck users are sharing the same ride. You send a local message, "Hey, I see you have a Steam deck! Do you have XYZ game, and if so, wanna play a few matches?"
A few hours later and you've made a friend, added them on Steam, and you already have to stop and prepare for arrival.

This not only would benefit the Steam deck, but it would set the bar for mobile PC gaming for the future.
Additionally, this is a feature update that could be done post-launch as most Wi-Fi cards already support Ad-hoc mode, and the additional functionality could be added to Steam in regards to Steam deck usage.

Thoughts? How could it be made better? How would you use it?
Feel free to discuss; I'd love to see what some of the brilliant people here come up with!