with most brokers it's possible to maintain a USD account in addition to a CAD account. The investor/client can then convert when & if he chooses.
client should never be forced by the broker to convert. Walk if your online broker doesn't offer a stable US account.
btw TDW is coming with US trading in rrsps. It's just a matter of time. Currently prepping system infrastructure.
i'd doublecheck that BMO conversion rate, it seems too low. The usual spread taken by an online is 1.90% one-way only. Canadian banks are not that far apart in currency conversion rates, generally speaking, so the other low rates set forth in this table might also be worth checking (not volunteering to do this, believe me.) If the information was gathered by word-of-mouth, i'm wondering if it's possible that the questioner/surveyor didn't phrase the question properly.
the exception would be IB with its superb forex trading capability.
however (more leaks) TDW is also coming with forex trading & multi-currency investing. Maybe even this year. Bet their website will really shiver with that one lol.