Caveats must claim at least one valid and acceptable interest in land. The drop-down list in box 3 of the eCaveat contains as exhaustive a list of interests in land as the legal staff of land titles could create.
The list is built dynamically and the items populated in it will depend on the nature of the caveator and on the nature of other interests already claimed in the caveat; certain interests can only be claimed by certain caveators and certain interests cannot be claimed in the same caveat as other interests.
If the interest that you are intending to claim is not in the drop-down list it is likely that it either is not a valid interest in land (a right of first refusal for example) or, if it is, that you are not aware of the proper name for that interest in land (a pledge of land to secure a real estate broker’s commission creates an equitable mortgage).
The list in box 3 allows a caveator to choose, “other” to enter an interest in land that is not on the drop-down list. Please consult with the district registrar prior to doing this to ensure that the interest you are claiming is a valid interest in land and to make sure that it is not already on the list with different wording.
It is both the right and the responsibility of the district registrar to ensure that the interest claimed is a valid interest in land.