If you are an average person and you notice that changing the ID in the URL to another number gives you access to data you should not see; you aren't some elite hacker as many of the news articles try to portray you. So expecting from them to use a GPG Key while they only have their ISP provided webmail will be near impossible for them to do under half a days work.
Especially as most GPG tools are very unfriendly to use.