Do you have a reason to be in their condo so that you would have opportunity to hide it in an inconspicuous place? Once there, when they complain about it, you offer to find and correct the problem for them in return for three months of their being quiet as church mice.
Hey it's as good a solution as anything else here.
(We lived in an apartment complex for awhile with a neighbor directly over us who walked across the wooden floor in stilettos--a lot--and who lifted (and frequently noisily dropped) what sounded like weights. Also a loud stereo. We knew we weren't there for an extended period though so we toughed it out. The neighbor was eventually evicted for non payment of rent. As a parting shot, she super glued all the doors (including cabinets), all drawers, and all windows shut.
It made me really glad that we decided not to tick her off while she was still there.)
(For ballast when the dog is barking, get that album of the dogs barking Christmas carols.)