Collusion?

Today I saw Timothy McGrew's presentation on the Gospels at the Stand Firm conference:

http://projectthreesixty.org/index.php/2018/04/23/why-are-there-differences-in-the-gospels/

He did that last month (March 24). I did two posts on the same subject this month (4/18 & 4/19):

http://triablogue.blogspot.com/2018/04/a-broad-view-of-ipsissima-vox.html

http://triablogue.blogspot.com/2018/04/silly-putty-jesus.html 

There's so much conceptual overlap between his presentation and my two posts. We both quote from the two Wallace papers. We use very similar arguments.

A redaction critic would assume some literary interdependence. I redacted him or he redacted me. 

But he didn't have access to my posts since his presentation was given 3 weeks before, while I didn't have access to his presentation, which was only uploaded onto the internet today (at least, that's when I first saw it). And I only had access to the Wallace papers as of 4/17. 

What are the odds that my posts are independent of his presentation, and vice versa? What are the odds the we're both quoting from Wallace's two articles, less than a month apart? Just coincidental? How to account for the parallels. 

Yet, as a matter of fact, the timing actually precludes comparing notes. That illustrates the pitfalls of redaction criticism.