Of course, there are hybrids. Festivals are fields with a ticket-sales funnel attached. An art tool like Photoshop can be a field one day (when you use it to explore color palettes or play with generative art), and a tube the next (when you use it to accomplish a quick task).
There's still usually a dominant aspect. Just ask: How do the people who make Photoshop (or the festival) measure their success? Is it by the number of people through the funnel? Or by what happens in the field?
Similarly, ask how it's discovered by users or funded: if it's discovered (or funded) because of the numbers of clicks, downloads, or purchases, it's a funnel. If it's discovered (or funded) because people talk about what it's like to live and explore in it, that's a field.
to add
Planning and brainstorm meetings are fields for growing funnels. A festival is a ticket funnel, plus a field. A creative space is a field with little tubes inside, as inspiration strikes. Even very straightforward funnels—like scaling a business while keeping it a lively place to work—require the creation and maintenance of fields (for creativity and honesty of employees, for instance).