NodeBB core doesn't have anything to prevent this. But plugins can be made to prevent multiple accounts from the same IP etc although it can be easily by passed.
Is there any hook to detect a plugin's uninstallation?
If for example, a plugin may insert data into database, then when uninstall this plugin, how could we hook this event so that we could do some data deletions.
@jiangcaiyang the problem is, even if there is a hook built in... using ACP is not the only way to uninstall a plugin. You can uninstall it using npm or delete the folder from npm_modules directly. The hook won't be called in those cases.
@pichalite My purpose is, if some one follows the official instruction by uninstall it via ACP page, he will get unused old plugins' data deleted automatically ffrom database. Thus reduced the redundant data. The other way however, does not take this action. so the advised way is to use ACP to uninstall it.
@jiangcaiyang you can use these hooks for plugin activation, deactivation and uninstall
action:plugin.activate action:plugin.deactivate action:plugin.uninstall