Since referendums are the embodiment of the popular will, if major political issues such as amending the existing Constitution, writing a new constitution, or even instituting changes in sovereignty-questions to be dealt with at the constitutional level-are placed outside the purview of referendums, referendums become nothing more than so-called "bird cage" referendums. This type of democracy is limited, incomplete and points up the fear of and resistance to the popular will.
同樣地，公投既是人民意志的展現，因此若將修憲、制憲，甚至主權變更等原屬憲政層次的重大政治議題排除在公投範圍外，則不啻是一種「鳥籠式公投」，這樣的民主仍是有限的、不完整的，也顯示出堅持設限者對人民意志的畏懼與抗拒。