If a product does not have a price entered, having the system code render should not be the default output.
Looks like the shortest way around that is with a conditional:
{% if this.mightNotExist %} {{ this.mightNotExist }}
{% endif %}I think the current behaviour is expected; null/empty output should not fail silently.
(too bad the filters also choke on nonexistent tags; {{ this.mightNotExist | append: "" }} would have been a tidy solution)