Under my understanding the terms of the US "do not call" law, companies are EXEMPTED from the ban on calling a registered number if (amongst other things):
You have expressed a preference for or interest in their products
They have done business with you in the past
They are conducting a survey
They are charitably-driven
I noticed that since we were listed on the "do not call" list, we receive more "surveys" than before. These surveys are usually eventually commercially-linked, and so I refuse to take part in them. When people want my input or data and I'm not being paid to help them, or I haven't decided FOR MYSELF that I want to help them, I stop the "survey" ("
thinly veiled sales-pitch" is more likely) and tell them that I don't want them to call me back again.
Remember also that the 'do not call' list expires and has to be renewed every few (five?) years, and if you let it expire, there's a convenient 31-day 'delay' while you're re-enrolled. (All of this is as a result of lobbying by the tele-sales industry.) -So renew your listing BEFORE it expires. If in doubt, do it now.
[edit] there's apparently been some push-back against the 5-year 'expiry'...
http://www.ftc.gov/opa/2007/10/dnctestimony.shtmKeith