  Recently, the CMS collaboration has reported their search for electroweak
instanton-like processes with anomalous $B+L$ violation assuming multi-fermion
but zero-boson final states. On the other hand, many theoretical studies
suggest that anomalous $B+L$ processes may have an observably large production
rate only if their final state contains a large number of electroweak gauge
bosons. In this paper, we compare collider signatures of zero- and multi-boson
events of anomalous $B+L$ violation at the LHC and derive an upper limit on the
cross-section for the multi-boson process by recasting the CMS analysis.
