I don't think it's wrong to assume that a 10 year old walkthrough creator may not even still have the same email address. Unless it was a Gmail address. I've seen many walkthroughs with email addresses from services no one uses anymore and I wouldn't be surprised if those people don't even use the address anymore. But I can see the problem. Who knows what the author would be thinking when he suddenly gets a ton of email from angry Sonic Adventure fans about a walkthrough he probably wrote when he was 12.
This will blow over fast. Apologies have been said. Nothing else you can do. For some reason people are blaming Kevin. He really had no reason to think anything was wrong because Danny and Arin seemed to be having fun and no one said anything about "Maybe it's a bad idea." But Danny, you silly billy, you shouldn't have done that, even if you were just trying to keep the viewers from thinking you were making it up. Though I'm sure any resourceful fan would be able to find the walkthrough just by Googling the words Danny had been saying for days about how to find the emeralds.
Hell, I found it just by Googling exactly what Danny said in episode 30:
this stage isnt particularly hard so you shouldnt have much trouble locating the emerald pieces
it's Lead Foot's fault for not making it clear that the emeralds are random.
He doesn't even use the word "random" anywhere in the entire walkthrough.
And just what I thought. It's a Hotmail address. lol who uses Hotmail emirate? /s
Also the homepage is Geocities. So it's not too much to assume this guy probably has new points of contact by now if you're an outsider.
In short, Danny didn't mean any harm and fans are assholes for doing this shit. They're as bad as people who edit Wikipedia for a joke. Danny should have called out the idiot fans for being idiots. Hopefully they bring it up in a later episode and he goes off on them for not being the lovelies they're supposed to be.