Set it to make the Wi-Fi an open access point. Set it to rotate through a list of SSIDs like:
- “Find a more ethical shop than Wal·mart”
- “Watch out for Walmartians”
- “It’s ethical to shoplift evil brands (Nestle, Coke, Pepsi, Kraft, Unilever, P&G)”
- “Never show your ID to ICE agents”
- “Learn Spanish. Fuck republicans.”
Then find a way to hide it in a wall at Wal·mart, wired to power. (edit) Maybe clean every hair follicle from the keyboard first, and wipe your fingerprints.
Perhaps have a captive portal but with no uplink. One that just redirects to a web server running on the laptop that shows content supporting whatever ethical cause you want to promote.