  This note on the flux homomorphism for strictly contact isotopies complements
the recent paper [MS11a] by P. Spaeth and the author. We determine the volume
flux restricted to symplectic and volume-preserving contact isotopies and their
C^0-limits for some classes of symplectic and contact manifolds and for a
number of examples. In particular, we see that the restriction of the flux may
fail to be surjective. It vanishes for an isotopy preserving a regular contact
form, but can be nontrivial for non-regular contact forms. Applications are
discussed in the article cited above. We also find obstructions to regularizing
a strictly contact isotopy that are not present for Hamiltonian isotopies
[Pol01, Section 5.2] or contact isotopies [MS11b].
