I don't think you should tell your kids not to go to college. They should make their own choices. Give them a fixed amount of money, date when they're expected to move out the latest and a chance to make choices on their own, whether it be college, travel, new car or own business. I sometimes wish my parents wouldn't have secured it all for me and I had to figure out how&what I want to do with my life on my own. Maybe then I would've appreciated my current situation and wouldn't be so afraid of making less mainstream and perhaps also wiser and more economical choices.
Save your and your children's money and leave that experience out, unless your children are so academically capable that they can earn very generous, close to full ride scholarships (and hence also show that academic work is relevant for their future plans) and pay for it on their own. I might not be the one to speak as I'm still a freshman and European (though I do attend a LAC), nevertheless after 3 months of studying I've already started to question the worth of my ''elite'' (yet in comparison relatively cheap) education both money and time wise, although yes- admittedly it's both challenging and FUN. But even though my parents are paying for everything (and it is certainly convenient) I am considering to drop out after the first year if nothing changes, because I don't see how this would lead me to discovering my own unique path and set of values.
Furthermore, the fact is that nowadays unless you're going for something super-technical like engineering, architecture or life&earth sciences, your education might even harm your chances for employment, especially if your grades are average. Somebody with no degree but tons of experience and relevant accomplishments looks a lot more impressive than somebody with a degree and same accomplishments, because people simply like to blame the accomplishments on the education, which in reality is rarely the case. Therefore, yes, college is an experience, but it doesn't really employ you and there are experiences such as 4 years of traveling, working and volunteering that are far diverse, challenging and thought provoking than the 4 years of a homogenous campus bubble experience.