One remark, before we get another Canon/Nikon discussion:
the two sensors also differ in technology: one is a CMOS sensor, the other a CCD.
That difference might be a lot more important than the brand on the box...
The method used for the camera measurements is described in more detail here:
http://art-si.org/PDFs/Metric/EPMurphyThesis05.pdf, page 41-44.
According to that text, the data is recorded as RAW data, so, if a sensor sees
infrared, that ends up in the RAW data. The manufacturers
can not have done
any extra filtering beyond what appears in the measurements (in the optics/
hardware of the camera, what happens in their software is another question).
So if the CMOS/Canon sensor sees more IR, then that's what ends up in the RAW
file. Otoh, sensitivity at 700 nm is only about 0.05, and falling, so total area
under the curve is probably negligable, unless you have a spot in your scene that's
very intense on just that wavelength.