Concern Over Bing Crawling AdWords Ads

A WebmasterWorld thread has some Google AdWords advertisers concerned that Microsoft's search engine crawler, BingBot, may be crawling their Google AdWords ads.

One advertiser said he noticed that Bing has indexed his AdWords click through tracking landing page URLs:

Was just checking some ranking in bing and noticed a result listing a url on my site that was set up for an adwords ad, now how in the world did they end up with that in their results?

example url: example.com/widget/?pk_campaign=adwords&pk_kwd=keyword

Of course, there are several ways Bing could have discovered the URL above.

(1) They actually did crawl and click on the AdWords ad (hope not)

(2) They use Internet Explorer data for finding new URLs

(3) Someone on the web linked to the URL and Bing picked it up.

(4) Server logs could have been open for Bing to crawl.

(5) A bug with the content management system

(6) and on and on... Are you concerned Bing is crawling your Google ads and costing you money?