Its a very day task that we have to request and unblock every IP of customers of recently unsuspended accounts (many reasons: unpaid invoices, etc).
Please, ignore login attempts of suspended mailboxes. Its always block customers and if a hacker try to login to suspended account, he will never login. There is no risk at all
Now, a lot of people is working at home. If an account is suspended, then we have to unblock IPs for all workers. This is an IP for a mailbox. Some companies have 15 , 20 or more workers... that means we have to unblock 15 or 20 IPs.... or flush whole firewall. The customer have to watch their invoices and pay them but sometimes the customer only remember to pay when their account is suspended. Then, we have to unblock all their IPs and this is a bad hosting experience. Please, consider add this feature