The policies describing the rights and obligations of Guaranteed Time Observers (summarised in Section 11.5 of the Call for Proposals) are defined in the Appendix 2 of the Council revised document ESO/Cou-996. In particular this means:

1. The user community must be informed of the GTO programs at the time of the Call for Proposals.
2. GTO Teams can either provide the specific list of targets, or the field coordinates and size to be explored. In both cases instrument setups and integration times must be specified. Like for any other observations, GT Observations are protected against duplication. OPC will reject proposals that will clearly duplicate GT Observations. However, GT observers do not have exclusive rights over the targets they intend to observe or over the science they intend to investigate. OPC can recommend observations of the same targets with different instrument setups or different targets of the same nature proposed by non-GTO scientists. Protection against duplications will be enforced only on a semester-by-semester basis. In the case of GTO surveys or focused projects taking a large fraction of the GTO time, i.e. Large GTO Programmes, the whole observing plan may be made public at once.