Of course he'd be using an alias. The realization hit just after the confusion, which registered with unfortunate clarity across Wanda's face. Of course he'd be using an alias and of course he'd want to be cautious; it wasn't as if they'd been worried about making friends, the two of them, when they'd first come to California.
Wanda felt that she ought to have realized, and she was immensely angry with herself - that is, after she's come around from her shock. The hat, the obvious nerves, the mumbling. She'd half intended to leave the door open just in case 'Mr. Frank' were a creeper - this was not a pepper-spray pocket day - but Pietro had shut it and she suddenly wasn't inclined to try to subtly open it again. This was private, this reunion.
"Robert Frank. '02 or '03, wasn't it? God, I am such an idiot." Because she should have been looking for foster family surnames as aliases. Should have been using them herself, instead of new names that she'd made up out of thin air. Cursing herself the whole way, Wanda stepped in to try and hug her brother. Brains, Miss Ana, do you have them?