The problem is pretty simple. You trigger Facebook's algorithms that flag the accounts. It usually depends on how many friend requests you send out, how many have accepted, reported, or not replied to your requests. It also depends on how complete your account is. Depends on how connected your friend network is. Lastly, time is another big factor. For example, the approval rates you must meet until the account becomes disabled usually differes for accounts less than 24 hours, 72 hours, 1 week, and 1 month.