There is the Railway Safety Act, the regulations that apply to railway companies, and a number of rules that have been developed by the industry and approved by Transport Canada. Each railway company has its own standard operating procedures as well.
At this time, the only way to monitor for things that people might be doing that they shouldn't be doing would be through the efficiency testing that the railways currently conduct, where they would have a supervisor-trainer ride with the crew. It is unlikely, during that time, the crew would be doing that type of behaviour. Other than that, unless there's some occurrence, there's really no other way to find out.
Part of the idea of having recorders, video and audio, aside from helping us with our investigations, is that it's a way for railway companies and Transport Canada, for different reasons, to see, for example, if the rules and procedures are being followed, but in a non-punitive sense. In other words, it wouldn't be for discipline, except if the sampling demonstrated an immediate threat to safety, which would be defined under the regulations.