Some days, one just knows... That one simply should not use the public yet "trusted" WiFi... And all it takes is a single look into the bus and see a passenger that looks "not supposed to be here". And what do you think? A rogue access point and rerouted traffic indeed...
So please be kind to yourselves and use your mobile e.g. cellular internet over wireless when not at home or at work. It takes a well-skilled hacker (as in cracker/individuals with evil intend) mere seconds to spoof your dns and inserts redirects to sites without hsts and cached keys. (especially if you tend to ignore certificate warnings or choose to accept that certificate they provide "once")
And should you still want to use the public/external WiFi, just like sex... Protect yourself, applying preventive measures... A VPN works sometimes like a condom ;) it doesn't prevent you from the stuff that is already inside, but it will at least keep the stuff trying to get in somewhat at bay!