Superstitions
Who needs superstitions when they have seen magic, right?
Wrong. There are actually a different set of superstitions different from that of the muggle world that pertains to the wizarding world. Most of them Valeria think of as pure rubbish, but there is one she truly believes:
Releasing a Portkey before it has arrived will result in death or serious injury.
It makes perfect sense, doesn’t it? You don’t know where you are between your starting place and the intended destination. Apparition can be dangerous (splinching!), and it has a similar principle to portkeys. Logical, definitely.