way back when...
in the US atc was required to point out jet traffic to other traffic as a matter of course...
even if seperated by altitude or heading.
and if brazil atc had done this just as a matter of course, eg: GOL AIR, JET TRAFFIC 12 o'clock, radar shows at FL360
at least GOL could have been looking...might have then mentioned not seen on TCAS (we mention that here in the states all the time)
the more technology becomes involved and the more good people become less involved you will get problems.