If I hadn't chanced upon the 'keyword suggestion' tool, then I may well have chosen a particular word as one of my Adwords, blissfully unaware that when people search for an activity which is deemed second only to murder in terms of unpleasantness by any decent society, they would have found my client and his kid's T shirt shop.
If no-one else sees a problem with this then none of you are the type of people I want round to dinner!
(And I apologise if none of that makes any sense only plain speaking, in your language, seems to incur a PR of 0 round here).
How are you supposed to know what horrible things people searching for will bring up your site?!
AdWords can block phrases and even restrict to exact phrases, this seems your best option. In my opinion the suggestion tool is helping you to avoid the problem; I suggest you use it to your advantage.
I've often approached standard page building from the same perspective, avoiding word combinations that might be inapropriate in another context.
Please see Terms of Service [webmasterworld.com] point 25 about moderation policy.
Whereas Overture seem to get too carried away when it comes to relevancy, Google go the opposite way. The relevancy is often left to the perils of the person placing the ad, at least for a little while, and often the ads run and run until the advertiser twigs they are not getting the results they thought they would get.
I'd suggest to all new advertisers that they start off with a list of exact match phrases [square brackets], if that doesn't work in terms of volume then go to phrase match "inverted commas" and if that fails then take off all of the safety valves and just go for it. I'd also be inclined to come up with a serious list of negative keywords -negative, one of which should almost always be the word "free", unless you are giving something away for free, don't pay for tire kickers, it will put you off Adwords for life.