Back to the OP's original question - it's a reasonable one to ask, given high-profile retentions of former Canadian officials in apparent retaliation for the arrest of the Huawei executive, along with some past instances of detentions. The risk is very low, but not non-existent. If there's a pattern, it's when an executive works for a company that has a dispute or difficult negotiation with a prominent Chinese company or SOE, or a government investigation of the company for legal violations. It's definitely not arbitrary - there's a purpose always. They don't just pick up a random American because they're upset with trade negotiations; they get the one they think can maximize leverage.

Hard to know without having you post things it's best not to post whether you fit into that risk category. As you mention public transit, it is possible if China Railway Rolling Stock is negotiating with your employer you could be attractive, but there are likely more attractive targets in the company who are more directly involved (and I assume you're not going for work because you mention not putting it on your visa application - they'll know who you work for if you're negotiating).

Anyway, I wouldn't worry about it, but good to be aware.