http://www.fai.org/downloads/civl/CIVL_2017_Minutes

Only flight recording devices that record both GPS and the
International Standard Atmosphere pressure altitude (QNE) in the track log are
allowed for scoring. It must not be possible to modify the barometric altitude
once track log recording has started. Flights will be verified using either GPS
track log or livetracking data. When live-tracking data is used as a primary
source of scoring, pilots must be able to produce GPS track logs as a back-up.
The FAI has the right to use all data collected in 1st Category events,
including track logs, and may publish such data.

"… Airspace violation checks rely primarily on the barometric altitude as
recorded on the flight instrument tracklog (the International Standard
Atmosphere pressure altitude QNE) and then when necessary corrected by the
scoring software for the pressure conditions of the task (QNH). Pilots may
submit a GPS altitude log as a backup log only in case of problems with the
primary barometric log."

"As an aid to competitors and when reasonably possible with the scoring system,
pilots that fly closer than 100m vertically or horizontally to prohibited
airspace will be listed in the scores for each task without penalty."

The Steward for the Brasilia worlds will formulate specifics of a 100 metre
"buffer zone" with graduated penalty provisions, to be approved by HG committee
and Bureau and then included in the local regulations. The plenary accepted that
the local regulations supersede Section 7A on this matter.