applewatch lock to owner
Someone in my neighborhood stole my watch and locked it to steal the apps and emails
Apple Watch SE, watchOS 10
If the watch was yours and locked to you, no one else should be able to pair it to their iPhone, use it or steel your apps. The only exception to this would be if they had your passcode. Notify law enforcement and use Find My on your iPhone to determine the location of your Watch. You can also Mark it as Lost and erase your Watch.
Here's more on what you can do.