laundromat placements are very common around here too, and definitely congregation endorsed. they help placement numbers (and therefore boost pride when filling out the report slip), and can always be used as "experiences" relating to informal service, ending in "..and you never know what fruit it will bear".
i knew a brother who would always leave a set of mags on a public telephone at a quiet bus stop on the way to the service group. that way he counted a placement of 2 magazines, AND the fifteen minutes of driving time to the hall because he "started his time".