Not a particular ad appearing on your site, but you should probably check to see what advertisers are there. You can do this in the Ad Review Center under the Adsense Setup in your Adsense account. You can see how much placement ads are earning you by going to Advanced Reports and in the Show Data by drop down menu, select Individual Ad and you will see a checkbox that allows you to see Contextual vs Placement ads separately.
If there are only impressions then dont worry but if you are getting cents form these impressions then dont do it otherwise google may ban your account.
If you are just doing it few in a day and you generally get good amount of traffic , then adsense wont mind that as long as you dont click on those ads, but if you get very few traffic and gets too many impressions from your side, then who knows what G will think about it
Well, if google will ban for refreshing the page after uploading contents, changing the ads position, blending the ads ' color then its definitely negative to publishers. When i modify my page contents i just keep refreshing to see if its alright or not?
Its not too bad, google will automatically block your IP from gaining credit if you have logged into google adsense earlier to that click or view. However, if you do it excessively - You will get banned.
If the publisher wont see or analyze his/her page, how can he/she knows if proper targeted ads are displayed or not and even can not know if the position of ads are properly blended or not according to the page texture or is there any ways to know these?