I don’t think it’s a jinx. I’d probably weigh how much of a reach the school is and how you think your kid (and you) want to celebrate…and how difficult a rejection will be or if they have other options they’re excited about. I let my kids buy merch from schools they toured and liked to get them excited, even a few they didn’t end up applying to. Rejections are hard, even for the parents. I’d just go with your gut feeling on it.