The use of criminal background checks (CBCs) – requests for information on previous convictions during the employment recruitment process – is growing worldwide. This article seeks to explain the proliferation in CBCs by examining whether novel legislation introducing mandatory requests for some jobs also leads to an increase in requests for CBCs for jobs outside the scope of the law. The present research makes use of survey data collected from individuals requesting criminal records certificates before and after the introduction of new CBC regulation in Spain – EU Directive 93/2011/EU – which established the obligation to request a criminal record certificate covering sexual crimes for jobs involving frequent contact with children. The analysis detects only a small and unsustained growth in non-mandatory checks following introduction of the new law. However, the results suggest that the danger of the new legislation lies in employers requesting certificates with a higher level of disclosure than is required for the positions on which checks were made mandatory by the new law. In addition, the growth in non-mandatory CBCs observed during this period seems to be related not to the new legislation but to the emergence of tech companies, raising alarm regarding the role of novel forms of policy mobility and the new collaborative economy in limiting the re-entry of individuals with criminal records to the labour market.