A few weeks ago I was in a small pre-organised group doing specific time trial training over a 100km route. On a long downhill section we picked up a hitchhiker we overtook who quickly inserted himself into our group of 6 without intro and then didn't work, which is fine in itself, but he also didn't allow anyone to move ahead of him; he stuck doggedly on the wheel ahead of him and so disrupted the rotation.

We worked around this rude individual, obviously, but he kept with us for a good 5km or so before he ran out of gas and allowed a gap to form that myself and 3 others in our group had to sprint across to rejoin our friends. All in all, not a train smash but highlights that impromptu tagging along can disrupt a training ride where you are unwanted and unwelcome.

Happily, this sorta thing is rare.