Hi Olafur,
I literally do not know, you should ask Ian why some requests do not get answered.
I do not think there is a single request I have not answered as the purpose of the verified access is to simply stop my server being swamped by search engines, bots and serial machine gun downloaders.
The only reason I would not answer a request, is if I have not received one. Reasons I may not receive one:
There are some IP ranges that are blacklisted at the firewall, mainly Russia, Ukraine, and some others from M247, all of whom are rampart form spammers and ignore abuse reports. Other IP's blacklisted are torr gateways because I'm sick of the attacks and abuse.
The only email server IP's blacklisted are in general RBL's, plus a lot of Syria, Turkey, Africa and Brazil. LeaseWeb in the Netherlands have a few blacklisted IP ranges as they ignore spam and abuse reports (as far as I can make out, they ignore any form of communication unless you are in The Netherlands). The web form works fine for these.
I have had a couple of people submit requests by my webform that I have not been able to reply to over the years due to an incorrect email address given but otherwise if it's a name I recognize, such as yours, I would contact you by other means.
Cheers