I don't quite understand how cloaking is related to AdWords here. If you are talking about SEO cloaking, it's not an advised practice, because Google gets very good at catching it. On AdWords, the check of Google is for the QS and there your CTR is the most important, so I wouldn't try fishy things for a 1-2 point of QS.
some people cloak their urls in adwords ads to test their offers quickly, but it is not worth discussing here since you DON'T want to mess with Google when it comes to adwords.
I can't get you dear so could you describe with proper line it's best for you and us and one more thing cloaking is how connected with adword
Of course there are ways to URL cloaking that google never catches. I would presume that here you are referring to the use of scripts to redirect/cloak URL's. If that indeed is what you are asking then IMO that is quite widely in practice. But of course its not legit but is is being done on a wide scale.
Cloaking means, "a human reading the site would see different content or information than the Googlebot or other search engine robot reading the site. Most of the time, cloaking is implemented in order to improve search engine ranking by misleading the search engine robot into thinking the content on the page is different than it really is." Accordingly Google Adwords will disapprove your ad copy whose content is irrelevant or goes at the webpage having irrelevant matter.