The recent increase of RDF usage has witnessed a rising need of "verification" around data obtained from SPARQL endpoints. It is now possible to deploy Semantic Web pipelines and to adapt them to a wide range of needs and use-cases. Practically, these complex ETL pipelines relying on SPARQL endpoints to extract relevant information often have to be relaunched from scratch every once in a while in order to refresh their data. Such a habit adds load on the network and is heavy resource-wise, while sometimes unnecessary if data remains untouched. In this article, we present a useful method to help data consumers (and pipeline designers) identify when data has been updated in a way that impacts the pipeline's result set. This method is based on standard SPARQL 1.1 features and relies on digitally signing parts of query result sets to inform data consumers about their eventual change.