I'm afraid you must be mistaken on what the command was? The /unlock command only is used to unlock a password-protected chest. You'd have to have gone to every single chest you own and hit them after using the command.
There is of course the /cremoveall command, which will remove every single lwc protection that you have (In the town world, the wild world doesn't use that) however as you can see here it gives you full warning in even red text that it's going to remove
every protection you have.
So I'm a little confused how all your chests are unlocked if you only used the /unlock command?
I hate to say it, but this is also why I'd double-check with the person or a member of staff after seeing the warning if it was the /cremoveall command that you used.