OP you are absolutely right and I'd had the same thoughts.
On the other hand many of us use products every day that we know aren't exactly good for us on the basis that the benefits outweigh the risks, especially, as in this case, if people see the advantages but don't personally experience any negative effects.
The issue is that the vast majority of people aren't aware of the harm that can be caused by pure essential oils. They're incredibly potent! This means that it's all the more important that companies take their responsibility seriously in keeping their customers safe and I don't believe Cheeky Wipes are in this instance.
Lavender is at least one of the 'safer' oils but it doesn't mean that it's without risk. There are, of course, other essential oils that can even interact with medications, potentially cause seizures, premature labour... the list goes on.
In this case the lavender won't be of any benefit to the baby but if people do choose to use it to make the wipes smell nice (and I do understand that) then one drop should be more than sufficient.