Chevrolet 2008 Tahoe Owner's Manual page 70

Third Row Seat — Two or Three Passenger
For vehicles with a two passenger third row seat, there
is one top tether anchor located at the bottom rear
of the seat cushion that can be used for the rear driver
side seating position in the third row. Never install
two top tethers using the same top tether anchor.
1-66
For vehicles with a three passenger third row seat,
there is one top tether anchor located at the bottom rear
of the seat cushion that can be used for either the
third row center or driver side seating position. Never
install two top tethers using the same top tether anchor.
Do not secure a child restraint in a position without a
top tether anchor if a national or local law requires that
the top tether be attached, or if the instructions that
come with the child restraint say that the top tether must
be attached.
Accident statistics show that children are safer if they
are restrained in the rear rather than the front seat.
See Where to Put the Restraint on page 1-60 for
additional information.