OK I will just use mobile data instead of public wifi's. But then my next question was, how can I guarantee that my mobile data cannot be intercepted. Doing a bit of internet searching I found articles such as this one: HACKER SPOOFS CELL PHONE TOWER TO INTERCEPT CALLS. which says things like:

Police Use Secret Device To Intercept Wireless Data - AskMen Mar 16, 2015 cell phone eavesdropping - GSM, 3G, LTE & 5G Cellular Cell Phone Tapping and SS7 Surveillance Cellular interception and monitoring technologies give our customers a technological edge. Our key focus has always been the development of spy phone & tracking related technologies for off-air interception of cellular phones and satellite communications. Untraceable Cell Phone Solution Google’s Sidewalk Labs Plans to Package - The Intercept Jan 28, 2019 This $1,500 System Can Intercept Your Cellphone Calls

Are your calls being intercepted? 17 fake cell towers

In the past, LI for mobile data traffic was requested in the SGSN only. The SGSN captures the IRI and the CC for most of the mobile data communications and, for LEAs, LI in SGSN was the first priority. In the case of data intercept, the CC-IAP is the edge router of the target subscriber. It intercepts the data stream identified by an IP How are my text messages being intercepted? Jan 10, 2019

Passive GSM Interceptor - cell phone eavesdropping

Google’s Sidewalk Labs Plans to Package - The Intercept Jan 28, 2019 This $1,500 System Can Intercept Your Cellphone Calls The device could be used by corporate spies, criminals, or private investigators to intercept private calls of targets. "Any information that goes across a cell phone you can now intercept," he Passive GSM Interceptor - cell phone eavesdropping Passive GSM Interceptor. The Tactical GSM Interceptor may be used to listen to voice calls, monitor text messages and capture forensic data. All cellular conversations and SMS are recorded on the hard disk of the laptop, allowing evaluation of the intercepted data at any time.