Hey Lalaloo,
Any account ID and/or access token that is entered in the plugin settings are deleted along with the plugin. Both the ID and access token are issued by the Social media entity that you are obtaining data from hence the reason you have to log into the social media account to get one.
Smash Balloon does not know, keep, or have access to any access token for your account. When you obtain an access token you are essentially requesting this info directly from the Social media entity and then entering into the plugin so when an API call is made to the Social media the access token is passed from the plugin settings to the social media source along with the data request.
If the access token is correct for the account then access to the account is given and the requested data is returned to the website where the plugin is installed and further managed for a feed display by the installed plugin.
If you have additional questions please let me know. In the meantime I hope your week is going great.