Probably a silly question, but can I send SD to someone by username alone?

I know this is probably a daft question, given there's a transfer option right there on the wallet page, but I've never actually done it. Can I transfer SD to another user with just their username alone, or do I need anything else like a key or confirmation code or anything like that? Like, say I wanted to send you 1 SD, would I need any info other than your username?