Doesn't that mean that person can use the preset too?
No. The exported preset files can only be used by the user who exported them. The only way for someone else to use your preset is if you give them the image files from the "my_presets" folder.
A nice solution would be a user hosted preset pack. It was a project started when FH first opened to the public, but the forum where it was hosted pretty much fell into disrepair. so-to-speak. Since then, I haven't seen the person who originally proposed it.
Essentially, they were having people PM them the preset files. They planned then on packing them into one large zip folder and hosting it through mediafire. The folder was intended to be updated every month with new presets.
It was clearly a mountain of work before we got the fabulous export button. Exported files are pretty slim. I don't see why this can't be implemented as a bonus package like the map-pack. Heck, I'd even lend some of my mediafire account space for it :3 if need-be.