Kevin,
There are differences and similarities.
Yes, the FORCES are very similar with bending and compression.
The big differences are the EFFECTS due to the dissimilar shapes of the two extrusions.
Resistance to bending forces is directly related to the structural shape of the element, as well as the composition of the material.
The foil is an almost flat wing shaped tube. Unsupported it has very little strength in the flat direction.
A crossbar is generally a round or square tube. This shape has the highest shape related structural strength in multiple directions.
Holes reduce the cross-sectional area of the foil shape by a higher percentage than the tube shape.
I don't believe the holes ALONE reduce the strength of either extrusion by enough to impair their performance.
The difference that I see and the potential problem, is the effect of galvanic corrosion, particularly in the foil due to the closed ends.
There is always some GC when stainless hardware and aluminum in contact.
In extrusions that are ventilated or get rinsed regularly, the damage is minimal.
The foil very small and GC COULD eat away a critical percentage of its strength.
A NACRA crossbar is very large and often ventilated or rinsed regularly.
BUT, even a crossbar can corrode enough to fail.
At the Old Spice - Wide Open, Open Regatta, on Pamlico Sound, I saw a Hobie 16 front crossbar snap approxmately halfway between the mast and end casting. Upon examination, we could see that the break occurred at the location of one of the jib track pop rivets. There was no outward sign of corrosion but on the inside you could see how the corrosion had eaten a ring around the tube.
I would be concerned that something similar could happen to a foil.
The hose clamp idea is the easiest solution.