Well to start with fixing phones especially is not something I fancy. That aside there are numerous cases of people's data being leaked when the drop their devices at the repairers to get it fixed and that actually prompted some companies like Samsung to add a repair mode feature to their flagships virtually making the device non functional without the owner's consent.

As for public WiFi and ethernet cables well it happens but not very common in Nigeria if you observe you may notice scams are arguably more common than hacks.