Great to see this is cleared up. I’d also recommend adding the echo to your real-world example on your documentation page.
So this: <?php echo types_render_field("field-name", array("arg1"=>"val1","arg2"=>"val2")); ?>
instead of this: <?php types_render_field("field-name", array("arg1"=>"val1","arg2"=>"val2")); ?>
I added it (my issue was the prefix), but I can see how someone might not. There’s never a danger in being too clear.