Wesley Hill points out:

http://www.fai.org/downloads/civl/SC_7A

5 SCORING 1ST CATEGORY EVENTS

5. 1 General

The detailed rules for scoring 1st Category competitions are now contained in
the document CIVL GAP - Centralised Cross-Country Competition Scoring System for
Hang-Gliding and Paragliding. In case of conflicts between this document and the
CIVL GAP document then the CIVL GAP document shall take precedence.

http://www.fai.org/downloads/civl/SC7_GAP

4. 3 Altitude

Altitude evaluation is based on GPS altitude, as given in GPS tracklogs.

4. 3.1 New altitude measurement

Starting January 1st, 2015, altitude evaluation is based both on GPS and
barometric altitude, as given in GPS tracklogs. Only GPS tracks where GPS
altitude is given in reference to the Geoid4, as delivered by all commercial GPS
modules, will be accepted in CIVL’s FAI Category 1 events.

By default, in CIVL’s FAI Category 1 events, the altitude values used in final
glide decelerators and to determine altitude bonus in stopped task are
calculated from a combination of GPS and barometric altitude, using the Dimov5
True Altitude algorithm. To score tasks taking into account the calculated true
altitude values, a score keeper must either pre-process the raw tracklog files
with the software published by Daniel Dimov, or, if supported by the scoring
software, use the built-in functionality of the scoring software to the same
effect.

Organisers may choose to use the less accurate pure GPS altitude instead.

Airspace violation checks rely exclusively on GPS altitude for the time being.

You Flytec 6030 or Brauniger Compeo+ prominently displays
Barographic altitude (although you can get these instruments to display GPS
altitude in a user field). You can see why this might be a problem in the 2015
Worlds in Mexico if they set any altitude limits.