And customer confusion would happen with just about any product that you could even consider putting their logo on. Because they certainly have put it on just about everything or have licenced others to do so.
There are several factors that are looked at when determining if there is a likelihood of confusion so just because a product uses a trademark design does not mean consumer confusion is generated.
One factor that a court considers is the strength of the senior user's mark - and Harley Davidson certainly has a strong recognizable mark.
Another factor is the similarity of the marks - and if the wood burning reproduces the logo or name well, that can lead to consumer confusion.
The similarity of the goods is another factor. A single wood burning done at a customer's request with a customer-provided design is unlikely to confuse consumers into thinking the single wood burning is a Harley Davidson product.
Is Harley Davidson likely to create its own wood burning products? Probably unlikely.
If a trademark is used in bad faith (with the intent to capitalize on the senior user's fame), that can lead to consumer confusion. If a single wood burning is created for a single customer at the customer's request, this does not support a bad faith use.
Another factor judged is the sophistication of consumers. Will a consumer distinguish a single wood burning that has a Harley Davidson design from Harley Davidson goods? Probably.
If consumers are SHOWN to be confused over the origin of the goods (believe all of the wood burnings are Harley Davidson products because one wood burning uses a mark), however, that can support an infringement action (or, more likely, an injunction).
The quality of the goods created also need to be considered (and this gets into the possible dilution of a mark that FlyingRon mentioned).
When speaking of consumer confusion, it will be the average reasonably bright consumer that is looked at. Although the mark might be recognized, it seems unlikely that consumers will think the wood burning is marketed by Harley Davidson, if the marks are not used to promote kannae's business.
Obviously avoiding all unauthorized uses of others rights-protected material is legally safest. I do not see, however, that the described use here is a trademark issue of much concern. It can be a copyright concern.