I am just finishing Kay Ryan's The Best of It, and I realized something about poetry. Everything in it is intentional. You never encounter a typo, or an accidental tweak in the grammar, or an agreement problem. Certainly, there are some deliberate unusual usages here or there, depending on the poet and the work, but the point is that the poem is as the poet wants it, because they are careful and care about every mark on the page. Anything less is not writing poetry.