These newspaper boxes take up public space, and most of the 'free' boxes are not even news publications but advertising circulars and such. One argument against leaving street memorials up in perpetuity is that they take up the public space.
I dug into the issue a bit deeper, looking into the permitting process for placing items in public space. Most public space items fall under the purview of the District Department of Transportation. The Public Space Office at DDOT issues permits for the use of public space by private parties. Surprisingly enough, newspaper boxes do not require public space permits. DDOT is considering changing this, though.
I dropped a line to Gabe Klein, Director of DDOT, about what, if any permits, would allow a memorial/dedication on public property. According to Aaron Rhones at DDOT, there is no permitting process or policy for such items at this time. Rhones did acknowledge that this may be a good topic of discussion moving forward, as DDOT revisits some of it's public space policy.
Around the District we have all sorts of strange and odd memorials. Example, the Maine Lobsterman memorial. There are others as well. Now I don't know who owns the land at 6th and Water St. SW, so I don't know if the Lobsterman statue needs a public space permit. It may be on Federal or private property. However, I think this is a topic worth discussion.
There is a difference between the ghost bike and makeshift memorials that appear overnight, made up of candles, stuffed animals and postcards. However well-intentioned these may be, they are temporary by nature. Time and the elements take over, and eventually the memorial needs to be removed. In these cases, the 30-day policy at DPW makes sense. Soggy pieces of paper and melted candles, even if thoughtful, become an eyesore and a mess.
If a group or an individual wishes to take the time to create, install and maintain a memorial, there should be a permitting process to allow this. I find it ridiculous that I could place a few newspaper boxes on the same site where the ghost bike was and those could remain in perpetuity, no matter what literature they were dispensing.
Some argue that if we allow street memorials to remain forever, they will be everywhere and public space will be consumed. First of all, this is a ridiculous argument. While it is true that everyone dies, not all of us will have people clamoring to erect memorials in our honor. Sorry for the ego blow people, but we don't all (live) or die in a fashion that is worthy of a public memorial.