What are the implications of art.11 of the European Convention on Human Rights: the right to freedom of assembly and association?

Article 11 of the Convention reads: "Everyone has the right to freedom of peaceful assembly and to freedom of association with others, including the right to form and to join trade unions." It has been suggested that limiting the number of pickets on a picket line to just a handful of workers may be construed as a denial of a worker's right to freedom of peaceful assembly.