Well, they are ALL information gathers.
However, there are some that have various issues.
Some times they have tracking issues.
Some times they think you have completed the survey else where.
Some times the survey has actually ended before you complete it.
Some times it is a cheat.
But yeah, it makes you wish they were in front of you so you could
feed them bread balls or smash maters in their nose or make them
do 100 pushups or pin their ears back or dye their hair or make them
wear hard curlers to bed or make them walk on rocks for a month
barefoot, or make them drink cheap cola, or force feed them dog
mints, or......
Yeah, it kind of pisses one off.