I recently was outside looking for public wifi because my android mobile internet wasn't very good. I went past a garage that had free wifi apparently, so I went up there and connected to their wifi.
However, despite being somewhat close to the garage, the wifi signal was still poor. I looked and saw a few dozen meters away some apartments and I realised that I could be connecting to some unknown wifi in the apartments,run by someone bad. I then quickly disconnected and left.
The good thing was that I was only on the wifi network for about 10-15 seconds and I didn't visit any websites where they could look at my data. Also the signal was really really weak. Though I looked online and found this:
Once a victim connects to the rogue Wi-Fi hotspot, the host hacker can then intercept data and even use tools to inject malware into the connected devices.
So I feel a bit uncomfortable. My phone also acted a little strange, saying it had 15% battery still and then suddenly 1% and switching off. Then when i plug it back in to recharge, it suddenly says it has 40% battery.