Yes! Thank you! Finally a voice of reason.
In fact I've been doing some more testing since I got my AirPods and just found out that the issue is much worse than I thought. It turns out the screens doesn't turn off at all sometimes. I keep my iPhone 7 in my front jeans pocket, screen facing my leg and pressed against the fabric of the pocket.
In this scenario I ask Siri to resume playback of music, then the display lights up and the contact between the display and my leg prevents the display from shutting off. If the phone is lying completely still the display will turn off after about 30 seconds but because the phone is constantly moving because of walking or biking, the touch screen is activated.