Abstract <p>Two ways of implementing unilateral holonomic constraints with piecewise smooth boundaries are considered. Examples are given that testify both in favor of the proposed methods and against them. The sensitivity of the equilibria of a system subjected to holonomic constraints with piecewise smooth boundaries to the way these constraints are implemented is also discussed using examples. Two problems from the mechanics of systems constrained by a pair of inextensible weightless tethers are considered. In one of these problems, which is most likely academic in nature, equilibria are found and small oscillations near these equilibria are studied. Another problem relates to tethered systems deployed near a uniformly rotating celestial body. For it, the relative equilibria of a load suspended on a pair of tethers are found, and sufficient conditions for the stability of these relative equilibria are studied.</p>