I was configuring a new Sitecore 8.1 instance. It’s a vanilla, straight-off-the-installer instance, and yet I noticed that the node’s request validation was off:

<pages validateRequest="false">

This did, at least, come with a comment above it:

If requestValidationMode attribute of httRuntime node is set to 2.0, Sitecore requires this setting to be set to “false” for Sitecore client to work and it shouldn’t be changed. You can however set ValidateRequest attribute in the @Page directive to “true” for your layout .aspx files.

This is bonkers. The default configuration for this site is to remove request validation on my brand new Sitecore instance on the off-chance I should want to configure it to use an older, non-default requestValidationMode. Instead, I should stumble across this comment in the web.config file and add the appropriate attribute to all the layouts of my solution. And someone thought that this was a good idea?

Even if I were upgrading and I did rely on the httpRuntime requestValidationMode being 2.0, I would prefer that this was set to true, with instructions for how I should handle it in the case of an upgrade.

Crazy. One to be aware of.