The idea of spreading a leap second over a longer period is not unique to Google e.g. www.quadibloc.com/science/cal06.htm
The idea itself is actually rather obvious.
The time-smearing technique reminds me of how the Erlang platform (ERTS) adjusts its internal timekeeping to changes in the system's clock. If the system's clock jumps, then Erlang makes its internal clock tick faster or slower than the system's clock by at most 1% in order to resynchronize.
Most good ideas are obvious in hindsight. ;) But AFAIK, Google was the first to do this live and in production by hacking NTP, which is (apparently?) the same as what Amazon is doing.
What if in a dst jump. It had. Pay namrog84 $100 at 1:30am. Then 2 rolls around and it's 1am again and now I get paid a second time. Win! But if dst was smeared over a day. This would be easily prevented.
