  The success of recently proposed models for describing rapidity-gap events in
DIS at HERA, in terms additional colour exchange between the struck system and
the proton remnant in boson-gluon fusion events, are found to rely heavily on
the absence or artificial suppression of perturbative gluon emission in the
forward region. A model without such suppression is presented, which cannot
describe the rapidity-gap events without a pomeron-inspired mechanism.
