The US military frequently uses the abbreviation "BLUF" (Bottom Line Up Front) for the same purpose as TLDR at the beginning of an email. It's not like the idea of tldr is some perversion born of the Internet.
One of my favorite pieces on writing is "Effective Writing for Army Leaders," available at http://www.au.af.mil/au/awc/awcgate/army/p600_67.pdf . They have hilarious side-by-side comparisons of poor and good writing, such as pg. 13 and 14 (pg. 7 and 8 by page number). I found this during a brevity kick I had after reading David Sirlin's "Writing Well."
That's pretty awesome! Although I think the elements of the "poor" example that draw attention to some potentially pertinent information shouldn't have been removed. (For example, the fact that the applicant is not mission-essential during a training cycle, and that given he has not previous cold-weather injuries, he may be less susceptible to them.)
A lot of people won't even read an email unless it as a BLUF
Sounds like the perfect time to slip in a clause in the form, "by not taking any action, you agree that..."