Why?: hundreds of empty files named wp-cron.php?doing_wp_cron.

In the home directory of the nginx user I have hundreds of empty files named wp-cron.php?doing_wp_cron.

So my questions are

1. why…?
2. can I delete them…? .
3. and how do I stop then regenerating?

Thanks

Ah… worked it out, though normally I rely on the traffic of the blog to hit wordpress’ fake cron I did have a daily crontab with wget to make sure site was fresh just before doing an export for an integration… but to stop it downloading the response of the request (in this case an empty file) you need to add the –spider option

31 0 * * * wget -qT 30 --spider http://www.example.com/wp-cron.php