Individual liability for unlawful acts during strike

Liability for unlawful or prohibited acts committed in a strike or other concerted mass action is legally determined individually, not collectively.[1] Article 277[2] of the Labor Code does not hold the officers of a union responsible for an illegal act of another officer:
Art. 277. Prohibited activities.

(a) No labor organization or employer shall declare a strike or lockout without first having bargained collectively in accordance with Title VII of this Book or without first having filed the notice required in the preceding Article or without the necessary strike or lockout vote first having been obtained and reported to the Ministry.

No strike or lockout shall be declared after assumption of jurisdiction by the President or the Minister or after certification or submission of the dispute to compulsory or voluntary arbitration or during the pendency of cases involving the same grounds for the strike or lockout.

Any worker whose employment has been terminated as a consequence of any unlawful lockout shall be entitled to reinstatement with full backwages. Any union officer who knowingly participates in an illegal strike and any worker or union officer who knowingly participates in the commission of illegal acts during a strike may be declared to have lost his employment status: Provided, That mere participation of a worker in a lawful strike shall not constitute sufficient ground for termination of his employment, even if a replacement had been hired by the employer during such lawful strike. (Emphasis ours)
A strike or mass action which is legal does not become illegal merely because it is tainted by prohibited acts.[3]

[1] Shell Oil Workers' Union v. Shell Company of the Philippines, Ltd., G.R. No. L-28607, May 31, 1971, 39 SCRA 276; A. Soriano Aviation v. Employees Association of A. Soriano Aviation, et al., G.R. No. 166879, August 14, 2009.

[2] Previously Art. 264 of the Labor Code.

[3] Shell Oil Workers' Union v. Shell Company of the Philippines, Ltd., G.R. No. L-28607, May 31, 1971.