Final answer:
The statement that a wildcat strike usually occurs in violation of an existing no-strike clause is true. Wildcat strikes are unauthorized by union leadership and breach the collective bargaining agreement, historically being a key method for workers to express unresolved grievances.
Step-by-step explanation:
In most cases, a wildcat strike does occur in violation of an existing no-strike clause in a labor agreement, making the statement True. A wildcat strike is an unauthorized work stoppage that occurs without the sanction of the union leadership and often in direct violation of a collective bargaining agreement, which typically includes a no-strike clause. Such actions are usually a result of workers' grievances that they feel are not being adequately addressed by either their employer or the union.
In terms of labor history, the organized labor movement saw collective bargaining and strikes as critical tools for workers to improve their conditions, particularly after the Industrial Revolution and during the Great Depression. Strikes, like the ones in Toledo, Minneapolis, and San Francisco, have been pivotal in demonstrating workers' solidarity and grievances, although they may come at the cost of productivity and sometimes incite violence.