Ok, but the substance can surely be had in the body of the text? If the subject line can be shortened by using normal convention abbreviations that lose no meaning, then why make someone waste time by writing out the full version?
Often, a reasonably descriptive subject line could be done with way less than 15 characters. If the subject line that is under15 characters promotes enough interest, then other users will click on it.
I also think being confined goes against the FOSS way of doing things. I should be free to post with a subject line of less than 15 characters if I wish, no? 