It has always been my interpretation that the most that could be claimed by any taxpayer was 2 trips per person in their family.   Here's the blurb that is on the actual paper T2222 (which is usually the best way to figure out odd forms) 

"Under proposed changes, you can claim, for other (non-medical) reasons, up
to two trips that you took and up to two trips taken by each eligible family
member. You also can claim any number of medical trips taken by you or an
eligible family member. However, no more than two non-medical trips taken
by any individual (themselves or an eligible family member) in a year can be
claimed by all taxpayers combined"

I don't think I've ever not done it this way, so I can't say if it'd fly under scrutiny, but I think that my interpretation is correct.  

Kathi