Well that would be the usual boring answer from the guy down at the pub who isn't really entering in to the spirit of the conversation. How about this one... Be shot out of a cannon - that's pretty dangerous. But with a little thought we can make it safer. For a start, how big is the cannon? Where is it aiming? Can I wear a crash helmet? Can I land in a very large safety net? Can I get someone else to do it for me?
Of course, reading email can be a pretty dangerous business to, with all those requests from your bank, or someone else's bank, to make sure you validate your password just one more time. Or the links to special interest web sites eager to part you from you money. Or even some distant relative desperate to give you a share of those millions you thought were lost forever.
Of course we take precautions here, too, looking left and right, not doing anything stupid. But what if we are taken over by a feeling of wanting to know just what it would be like to be shot from a cannon?
The tempting invitation for the Cannon Shoot arriving in your inbox in the first place meant that your first antispam line of defence has been breached. Of course, you could still have some client software installed, but that has also failed you this time. So you click the Cannon Shoot _registration, but the site has been blocked by your content filtering safety net, phew! Someone's been busy rating dodgy websites on your behalf. Had you been able to access the site, download that little software application, then you too could soon be hosting your own _Cannon Shoot. Of course a compromised PC would still need to be able to install this little piece of malware. Even if that happened, here again someone has been working on your behalf making sure that even in this worst case, that software you'd installed wouldn't be able to call home for the latest invitation instructions for the Cannon Shoot.
If we didn't have antispam, content filtering, antivirus, and intrusion protection defences, pretty soon it wouldn't be safe to cross the road, you'd be dodging all those crash helmet clad cannon balls flying up the street.