In the history of co-operatives there are many examples where the Principle of voluntary association in co-operatives has not been observed. Cultural norms such as women being required to cease to be members of a co-operative when they marry or being denied membership because men are heads of households are a clear breach of this Principle. Some governments that used co-operatives as government controlled engines of economic development made membership of co-operatives compulsory. This too breaches this 1st Principle. The right of voluntary association to form co-operatives can also be frustrated by national legislative, tax and administrative systems which favour the investor owned model of business enterprise and do not take account of the specific nature of co-operative enterprise, hence the importance of co-operatives working politically to influence the legal, financial and administrative regimes in which their business enterprises operate. Breaches of the 1st Principle of voluntary and open membership do not accord with the letter or spirit of the founding principles of our co-operative movement. They frustrate the growth of co-operatives as autonomous voluntary associations of persons uniting to meet their common needs and aspirations.

In Nicaragua, Gladys Herrera plays the saxophone on the International Day of Co-operatives. Young people like her receive art, music, and environmental education and training from Soppexcca coffee farming co-operative. This is Soppexcca Co-operative's investment in young people and a way for the sons and daughters of its members to get involved with the co-operative.

If membership is compulsory, membership becomes tokenistic rather than an exercise of the fundamental human right to freedom of association. If members are forced to cease to be members, other than for breach of their responsibilities as members or because they no longer use the services of the co-operative, that too weakens co-operatives and is also a breach of this fundamental 1st Principle.

The voluntary nature of participation in co-operatives is an indispensable organisational trait that makes them viable and sustainable in competitive markets. Co-operatives cannot survive without the voluntary patronage of members who use the services of their co-operative and provide capital for it through membership shares which grant voting rights, on which they receive only a limited return, if any. The role of members as volunteers to serve as elected officers and on boards or committees is also a fundamental characteristic of co-operatives. In some co-operatives, the voluntary support of members for the daily operations of the co-operative is also essential to the success of the co-operative.

The statement that "Co-operatives are voluntary organisations" reaffirms the fundamental importance of people choosing to make a commitment to their co-operative. People cannot be made to be co-operators, nor should they be forced by governments or others to become members. Where economic pressures or government regulations encourage people to become members, co-operatives have a special responsibility to ensure that all members are fully involved and educated about the voluntary and open nature of their co-operative enterprise so that they voluntarily support it.

In some countries co-operatives, such as utility co-operatives, act as government-sanctioned monopoly enterprises. In these cases, membership is open to those residing within an authorised service territory. Within these service area boundaries, governments should not require individuals to become members in order to receive essential services. For example, co-operatives providing telephone or electric distribution services can provide a mechanism for those who seek service to obtain it while "opting out" of co-operative membership for religious or other reasons.

Open voluntary membership also means that members are free to cease to be members if they so choose. In some co-operatives, practical restrictions may need to be applied to members wishing to leave, though restrictions on leaving should be limited. For example, in a housing co-operative, a member may be required to assign the occupancy rights of the co-operative home they occupy to a new member. In an agricultural or worker co-operative, withdrawal of capital when a member leaves may need to be phased over time or subject to reasonable delays to avoid destabilising the soundness of the co-operative's finances, but the principle of a member's right to withdraw from membership should be respected.