Regardless of whether there's an engineer there or not it's incumbent on the captain to raise any defect in the tech log, for your own safety if anything as you may be the next person to fly the aircraft. I've rarely seen notes on control columns these days, vast majority of crews are very professional and use the tech log. On the few occasions I have seen notes one of two things happens; either it gets slung in the bin as 'no tech log entry, no defect' or it gets stapled to an MOR report and sent to Quality/CAA. I think most crews realise that keeping defects out of the tech log leads to less engineers being available and their own jobs getting slightly more dangerous.