Unregistered email accounts cannot change passwords or modify account settings until an email has been registered. Meaning not only is the account more secure because its never had a previous email that can be referenced in future recoveries even after changing it. You can also know for 100% certainty you have the original creation password, and that the account has little nostalgic value attached.
Please make sure to register an e-mail on the account before logging in on the off-chance the account gets locked based on the IP address change. Its difficult unlocking unverified email accounts. You can copy-paste both the username and password into the runescape.com main site to ensure typoes do not happen.
Photos: Zerk | BARROWS GLOVES + ANCIENTS + AVAS + LUNARS | NO EMAIL SET | 42 Def, 47 Atk, 51 Str, 43 Range, 46 Hp, 66 Magic, 43 Pray, 59 Combat | 0f5p03