I am also suspicious because I've had bad experiences starting squash plants in peat pots and finding that the roots have trouble leaving the peat and reaching vigorously into the soil. That's a bit different but I avoid those like the plague.
I asked MCG about these and they don't seem to think it's an issue and they would know better than me.
I guess it all comes down to personal preferences and experiences.
Thanks Tim and Dirt for your experiences & opinions, that's helpful info. It appears unanimous that removing the coir or peat block is best handling procedure for planting.
Dirt: you've coined the phrase I was trying clumsily to express, "death islands of peat".
Tim: I have a different take on nursery protocols. It is nurseries that have gravitated to using peat in large scale commercial production, particularly for perennials, in spite of the fact it's a poor choice for gardening consumers for all the reasons we know about. Maybe nursery folk don't know better than us gardeners after all, regarding what's best for planting-ready products, their focus is on what works best to make saleable products in a moisture-holding medium. They may not care or think about "easy plantability" once in the hands of consumers. When I go to nurseries now, I avoid peat-rootball plants like the plague.
By the way, had an interesting experience two years ago. Had a late harvest of seed on Japanese Arisaema sikokianum (in December). I went and bought some Pro Mix Seed Starting mix, sowed seed in a large container, but when the peat-based mix is dust dry, it's completely unwettable. A layer of water would just sit on top of the so-called seed starter medium, left it overnight, still did not sink in, I poked holes into the medium using a wire, left it another day, water still thoroughly repelled by the peat. In plant forums, someone suggested adding some mild dish detergent, which finally worked after 3 days of attempted soaking. I had excellent germination in spring, once the medium is wet, you can keep it wet, but NEVER allow it to dry out because it becomes a powerful water repellant when dry. It is the water repellant action when dry, that I suspect is the biggest contributor to "death islands of peat".