Facts
[E.] was the owner of Plot No. 3575, on which a restaurant was operated. [F.] owned the adjacent Plot No. 634. By a transfer and easement agreement dated August 26, 1960, [E.] ceded a portion of his plot to [F.], and the parties granted each other a boundary construction right. For the boundary construction right in favor of Plot No. 3575, they agreed that the owner of No. 634 grants the owner of No. 3575 the right to place and maintain the commercial extension and the bowling alley building at the new boundary. It was also agreed that no windows, doors or other openings may be installed in the extension and the bowling alley building facing Plot No. 634, and the owner of No. 3575 is permanently prohibited from operating an inn on the terrace of the bowling alley. This easement was registered in the land register as a "boundary construction right".
In 1990, the then-owners began to serve guests on the roof terrace of the bowling alley building. In 1997, A.X. and B.X. as the new owners covered the terrace. C.Y. and D.Y. as the current owners of Plot No. 634 then demanded that A.X. and B.X. cease the innkeeping operation on the terrace.
Considerations
The Federal Supreme Court upheld the judgment of the High Court, according to which the prohibition of innkeeping on the terrace of the bowling alley is to be regarded as a functional restriction of the boundary construction right and could therefore be established without a separate entry in the land register. The land register entry "boundary construction right" is too rudimentary to determine the exact content of the easement. Therefore, the easement agreement, which regulates in detail the location, extent and use of the boundary structures, must be referred to.
The prohibition of innkeeping on the terrace is directly functionally related to the…