Tablets are just as vulnerable as computers because they use the exact same wireless protocols to connect to open networks. In a public library, anyone sitting nearby with a cheap Wi-Fi pineapple device can intercept the data traffic of every connected device. They can see what websites you are opening and can even redirect you to fake login pages. To stay safe while working on your tablet, you absolutely need to encrypt your network traffic. I always recommend using a dedicated client like toggle.org/vpn-for-android to protect your mobile device. Once you turn it on, it builds an encrypted tunnel that shields all your inputs, passwords, and browsing history from anyone else on the same network. It is also a good habit to disable the auto-connect to open networks feature in your tablet settings, so your device doesn't connect to random unencrypted hotspots without your knowledge. It takes very little effort but keeps your files completely safe.