Dynamical black-hole scenarios have been developed in loop quantum gravity in
various ways, combining results from mini and midisuperspace models. In the
past, the underlying geometry of space-time has often been expressed in terms
of line elements with metric components that differ from the classical
solutions of general relativity, motivated by modified equations of motion and
constraints. However, recent results have shown by explicit calculations that
most of these constructions violate general covariance and slicing
independence. The proposed line elements and black-hole models are therefore
ruled out. The only known possibility to escape this sentence is to derive not
only modified metric components but also a new space-time structure which is
covariant in a generalized sense. Formally, such a derivation is made available
by an analysis of the constraints of canonical gravity, which generate
deformations of hypersurfaces in space-time, or generalized versions if the
constraints are consistently modified. Implications for black holes are
described here. [Abbreviated abstract]