I was serious in my reply. I've made multiple trips across the border recently. It is not any one thing or any one day. They have been revamping the system and hightening security for months. It is a very difficult time to predict that daily conditions. I've driven through twice without even having my ID checked... and I've sat and watched them search every car on other days.
If you are bringing back extra strength supplements... the situation is the same as always... hide it well and live with the risk.