Board Thread:Episode Discussion/@comment-14138255-20160214165601/@comment-24994749-20160216211225

Well, Penny and Ruby's friendship was built on very few interactions.

They met during "The Stray" for a few moments, then they met again during "Black and White". We know they didn't see each other again until "A Minor Hiccup", which presumably took place at least a month later. It doesn't seem like they got to interact during the Beacon Dance... so their next and last interaction before Penny's death was during "Never Miss a Beat." (again, around a month later) and it lasted like 1 minute.

If in like three months, with so little interaction, they built up that close of a relationship, I don't think a memory wipe will do much to them, unless Penny's personality is completely reprogrammed.