  Microlensing is generally thought to probe planetary systems only out to a
few Einstein radii. Microlensing events generated by bound planets beyond about
10 Einstein radii generally do not yield any trace of their hosts, and so would
be classified as free floating planets (FFPs). I show that it is already
possible, using adaptive optics (AO), to constrain the presence of potential
hosts to FFP candidates at separations comparable to the Oort Cloud. With
next-generation telescopes, planets at Kuiper-Belt separations can be probed.
Next generation telescopes will also permit routine vetting for all FFP
candidates, simply by obtaining second epochs 4-8 years after the event. At
present, the search for such hosts is restricted to within the "confusion
limit" of theta_confus ~ 250 mas, but future WFIRST observations will allow one
to probe beyond this confusion limit as well.
