Why withdrawing PayPal from mobile blocked my account temporarily

[Nil123]

The title says the case. PayPal said their system detected some unpermitted withdrawel so have blocked transferring money to bank temporarily. After this I had to fill up their security question form and then the block was lifted. Why it is so.

[eNumbered]

'Have you tried eNumbered.com? They offer anonymous bank accounts and an anonymou no-name debit card'
'paypal', 'paypal alternative http://eNumbered.com