Just got off the phone with Schwab's Global desk in Phoenix. Broker said there is no such trading problem for Schwab customers. Schwab trades directly with exchanges all over the world with the biggest in Canada and have no plans to change. 99.9 percent of orders out of the US for Canadian stocks will continue to go directly to Canadian exchanges for execution with that .1 percent possibly occurring if a better price can be found in the US or elsewhere. Not likely.

As an aside, the person believed that Scottrade does not trade directly on Canadian exchanges, that they do not have the direct connection that Schwab and other big brokers have and that the reason may be related to the high expense of such arrangements.

Cannot verify and just a possible heads up.