I think this post nicely illustrates the difference between "legal" and "polite/friendly". In most countries with legal codes descended from English civil law (and many other countries too), it is legal to take and publish photos of what can reasonably* be seen without expectation of privacy from public land (with the exception of lewd/harassing photos) for artistic or journalistic purposes.
Thus, John would have been well within his rights to publish this photo here without permission from the Motz family, but it was polite and friendly, as always, to ask first.
* 'reasonably' generally means no special actions to circumvent privacy measures - e.g. it would be legal to take a photo of someone's yard over a 2-foot picket fence from the sidewalk, but not to use a ladder to take a photo over a 12-foot fence from the same sidewalk.