Do owners have to maintain an availability or can they just lodge a patent and vanish leaving an idea protected which nobody else can touch. If not how do we locate owners to find out more details or be sure not to infringe.
The original applicants and inventors provide some contact information during the patent prosecution process. If they use a patent attorney of patent agent, their information will also be in the record (the best way to look these things us is via Public PAIR). As the patent changes hands from the inventors to a company and maybe them to a second company the information should be recorded with the USPTO's recordation office. It is like recording the transfer of a deed at the county courthouse. While not recording a transfer generates some risk to the buyer, there is no rule that says assignments must be filed.
Also, if the inventors still hold the patent rights they do not need to update the USPTO of their change of residence. There are reminders that the USPTO sends out that the patent owners should be motivated to get, but they do not need to provide address updates.
This can represent a problem for someone who wants to take out a license. In many cases the owner can be tracked down.