It would be a reasonable expectation, given this performance by The Honourable Senator Michael Duffy (Cavendish), for the senator to resign his seat (or at the very least, for Her Majesty’s Government for Canada in the Senate to remove the senator from its caucus). The Honourable the Senate of Canada, as an institution, should be extremely concerned at the public perception that this senator may have created through his impropriety, and steps should be taken to distance the Parliament of Canada from this particular member (perhaps a motion of censure would be in order).
Let’s be clear on the point of expenses, though, that there are rational and entirely appropriate reasons for the expenses of honourable senators to be higher than those of their elected counterparts. Members of the House of Commons represent only a single electoral district, whereas honourable senators* each represent an entire province. The greater travel costs alone, for senators, would necessitate a higher expense line. For the Senate to perform the functions that it is constitutionally charged to perform, and for regional interests to be effectively represented, these expenses are entirely justified.
(*Except for Québec senators, as they each represent one of twenty-four “senatorial districts”.)