[AndrewC]

CMBR didn't exist, you'd have a point.

It is no surprise that something that cannot be demonstrated solves something for which it was invoked. The CMBR existed prior to inflation. Inflation was created to explain properties of CMBR, so it is not unexpected that the properties of CMBR are consonant with the explanation. But, matter attaining a velocity of the absolute universal speed limit and then exceeding that limit is not an expected consequence. However, that consequence is hand-waved away.

[Physicist]

The CMBR existed prior to inflation.

Irrelevant. The CMBR is a general feature of Big Bang models. What did not exist prior to the Inflation model was the incredibly detailed anisotropy power spectrum:

The curve is the theoretical prediction, and the data are from the WMAP probe, which published its results in February. Oh, and the polarization of the background is similarly well-predicted.

Inflation was created to explain properties of CMBR

Any Big Bang model predicts a CMBR of some kind; the properties of the CMBR that Inflation best explains weren't even known at the time (see above). Inflation was proposed to solve the horizon problem (why is the temperature of the universe so uniform), the flatness problem (why do the angles of large triangles sum to 180 degrees) and the homogeneity problem (why are there no--or so few--magnetic monopoles).