I think it's really dependent on the management. I worked at an "unlimited vacation" job and Felton shame taking 4-6 weeks off per year. There was motivators for not taking vacation- profit sharing was dependent on your utilization rate. I happen to have a good reason to take the time (my kids holiday schedule) so I didn't mind giving up extra money for time. I never was approached about my vacation time and felt that I used it responsibly. I can see how some environments could push that into a don't take vacation culture though.

If this is what you want, why not offer 6 weeks of PTO and a firm policy? It removes the ambiguity.

I always take 6 or more weeks per year. Usually I have unlimited vacation. The few times I've been acquired by megacorps with ancient vacation policies I either "forget" to file for vacation and so does my boss, or I take unpaid time off.