Hey niro3, that’s a really important question. Generally speaking, yes, it is illegal to track another adult’s phone without their knowledge and consent. It’s a major privacy violation.
This is honestly one of the big reasons I stick with iPhones. Apple builds its whole system around user privacy and security, which makes it incredibly difficult for spyware to be installed without you knowing.
If you want to share locations with someone, the proper way to do it in the Apple ecosystem is with the “Find My” app. It requires an explicit invitation and acceptance, so both people are fully aware and have consented. It’s reliable and built right in.
I’ve always been a bit wary of Android’s open platform, as it can sometimes make it easier for malicious apps to slip through the cracks. The level of control Apple has over its App Store provides a peace of mind you just don’t get elsewhere.
Bottom line: always get consent. Using a feature like Find My is the best way to do it transparently.