I don't know where pogofish gets his information from but all the advice form cancer charities and health professionals is to use it.
Mostly from the same places & I don't think I've seen any that don't make it very clear that sunscreen alone is not a reliable method of protection. IME, they always stress the importance limiting overall exposure as well.
eg - Here, points 1,2,3,4 & 5, stress limiting exposure, sunscreen only makes it in after that at no 6.
http://www.cancer.org.au//File/Cancersmartlifestyle/LifestyleseriesBeSunSmart.pdf
CRUK says it with less words:
http://info.cancerresearchuk.org/healthyliving/sunsmart/staysafe/sunscreen/?a=5441
The link to the Mointuriser/cosmetic thing was on an earlier sunscreen thread that may not have survived the board crash but here is a reference to the change in Australian product description law that resulted from it. Where they were amongst a range of products stripped of any theraputic/effective value altogther:
Cosmetic Standard
Finally, a new Cosmetics Standard 2007 was made under the Industrial Chemicals (Notification and Assessment) Act 1989 and which came into force on 17 September 2007. The Cosmetic Standard changed the status of six categories of products (personal lubricants; face and nail products with sunscreen; skin care [moisturisers with sunscreen and sunbathing products]; antibacterial skin care; anti-acne skin care products; oral hygiene [teeth and mouth products]; and anti-dandruff hair care products) which previously treated as therapeutic goods and contains requirements regarding the composition and what claims can be made in relation to those products.
This Standard illustrates the various ways different products are regulated in Australia which sometimes is not self-evident. All cosmetic products and their ingredients must comply with the legislative requirements for cosmetics under the National Industrial Chemicals Notification and Assessment Scheme (NICNAS). New cosmetic ingredients (ie. those ingredients not already listed on the Australian Inventory of Chemical Substances are subject to notification and assessment under NICNAS (unless exempt) and all companies and individuals which import or manufacture cosmetic ingredients or products must be registered with NICNAS. In addition, a consumer product information standard made under the Trade Practices Act also applies to cosmetics and toiletries.
http://www.mondaq.com/article.asp?articleid=58812
Also Garland/Garland/Gohram is IIRC still the main research study into innefectiveness of sunscreens. Abstract here:
http://www.ajph.org/cgi/reprint/82/4/614
Only the US seems to have taken much notice of its findings & put protection claims under any sort of legislative control.
More recent stuff includes concerns about what sunscreen agents are doing to the world's coral. It seems that even a tiny amount of the stuff can do a lot of damage:
http://www.ehponline.org/members/2008/10966/10966.pdf
FOE on nanoparticles, which are another cause for concern (& not just in sunscreens):
http://www.foe.org/nano_sunscreens_guide/Nano_Sunscreens.pdf
Other nasty stuff - also applicable to many cosmetics:
http://www.sickamongthepure.net/avoiduvr/sunscreens/chemicalbarriers.html
Finally, if you can put on makeup over sunscreen, you are not applying it properly so its protection is negligible.
http://news.bbc.co.uk/1/hi/health/5190214.stm