Seems like you figured this one out but I will chime in anyways. Don't do it. Also don't accept certified checks unless you and the buyer go to the bank the check is drawn from.
PayPal's protection only covers items shipped, where you have a tracking number. Without that, your on your own. Buyer can say his account was hacked, funds stolen etc. That's on PayPal's own site.
In terms of certified checks, I can print one up right now, you can take it to your bank and deposit it, it will even be good for a bit until it actually finishes the trail. Your bank will attempt to pull the money back out of your account and if it's already been spent or whatever your liable for it. Ask your bank next time you go in, I did and that was the advice they gave me.
You can send spoof emails from any address you want, that's also why if you get an email from PayPal or hell, any email from a financial institute you don't click any links in the email, instead go to your browser and type in whatever site it is, log into your account that way. Also, for any private information make sure the site you are on or logging into is https instead of http, as the s means a secure socket and SSL encryption, other wise http is sending whatever information your filling out as plain text... you don't want that going over the net.
