They can be pretty sneaky in their attempts to trick the reader into at least opening their message. When I make that error I simply close the message and delete it. Even if you don't open it and delete it, it can still be "found" on your computer. When people say porn was "found" on a computer it's meaningless unless thy say WHERE on the computer it was found. Obviously finding pictures in a folder called "Last weeks's BBQ pics" is different than in a deleted mail/spam folder. Even finding it in a browser cache needs further clarification, as sometimes nasty popup windows can be spawned by accident when going to rogue sites.
If someone's browser is filled with the stuff showing an effort by the owner to find the material it's one thing, spam or accidential popups is another.
That is exactly the point I was trying to make. Was it here the other day I read an article about authorities taking a person's computer to look for evidence of tax evasion or fraud, found some porn and spent the rest of their time looking for porn?
If the press is trying to make a recently arrested person look as bad as possible then they are going to simply say "porn was found on the defendant's computer" and leave it to the reader to decide what that means.
When it comes to filing charges against someone the authorities are not going to be quite as discerning as you or I would be, especially if they are out to get that person.