From this link: http://social.technet.microsoft.com/Forums/sharepoint/en-US/61a953cc-6480-429f-bbee-a34988c1e031/how-to-hide-revert-to-template-status-on-the-spd-customized-pages

But if that's gone here it is:

Here is some information regarding this issue:

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When a wiki page is edited by SPD2010 in advanced mode the page will display a status bar message for all users regardless of permission level.

The current page has been customized from its template.

If user has adequate permissions a link to reset the page to site definition will be displayed as well.

The current page has been customized from its template. Revert to template.

1. Since the page is being unghosted anyways, the easiest workaround, without modifying the page with additional CSS to hide the message, is to copy the content of the page into a blank aspx page and the status message will not display since a blank aspx page is not based on a site definition.

a. Open the page in SPD2010.
b. Switch to code view or split view and copy the markup.
c. Click the site pages site object.
d. Right click in some white space to bring up the context menu.
e. Select New > ASPX and this should get you a blank aspx page.
f. Go into code view on the blank aspx page and paste the content you copied in step b.
g. Save the page and set it as the new home page by right clicking on the page and picking set as home page.

2. Option 2 is: Don't unghost the page.

3. Another option is to create a blank web part page and set it as the home page. This can be made easier by disabling the site feature called Wiki Page Home Page and will more in tune with what users are accustomed to from the 2007 days.

This site feature is on by default when an enterprise wiki is used to create a site or a 2010 team site.

Description:
Wiki Page Home Page
This site feature will create a wiki page and set it as your site home page.

4. You can use the CSS to hide the div that contains the status bar but this might block status bar messages you may want to see.

Depending on your upgrade scenario some customer's have reported that the default.aspx page found in a team site is not used after an upgrade.

I could not reproduce this but the page should reside in the root of the site and can always bet set back to the home page if this scenario does occur.

During my testing I tested the following scenarios:

1. Unghosted default.aspx and visual upgrade performed from the browser. Could not reproduce the issue. Wiki feature is enabled for new page creation.
2. Ghosted default.aspx and a visual upgrade performed from the browser. Could not reproduce the issue. Wiki feature is enabled for new page creation.
3. Ghosted default.aspx page with UpdateUserExperience flag used Windows PowerShell upgrade. Couldn't reproduce issue and wiki feature was disabled.
4. Unghosted default.aspx page with UpdateUserExperience flag used during Windows PowerShell upgrade. Couldn't reproduce issue and wiki feature was disabled after upgrade.

Each time I performed the upgrade I created a new web application. I didn't test this with web application that already had an upgrade performed against it but had the content database deleted.
If you do the UpdateUserExperience flag during the Windows PowerShell command and then enable the Wiki Page Home Page site feature it will create a page in the site pages library called Home.aspx. Your upgraded default.aspx should still be around but you will have a new home page.
The new behavior that is throwing folks off is because of the SharePoint:EmbeddedFormField. This is what the editable region on a wiki page uses. It does not like JavaScript and will strip it out. This is most likely for security reasons.
Also, if you add an image with SPD 2010 to the editable region it will get removed server side by this control unless you prove a path that that adheres to its standard.
The easiest way to figure this out is edit the page in a browser and take note how the src attribute is built. It should contain a URL like this:
/sites/team site/site assets/image.jpg
If you add it with spd the src attribute will contain a value like this:
../site assets/image.jpg
The SharePoint:EmbeddedFormField does not care much for this and will remove it. Other than JavaScript I could not identify any other markup that is changed.
The idea behind this new wiki feature is to allow users to create content without needing an HTML editor like SPD. More to the point, it is a wiki page and the idea behind wiki is to allow a lot of individuals to add content without allowing for unsafe markup that could harm your users/site due to the open nature of wikis.


OR

Insert a HTML Form web part. Replace the source code with the following:

<style type="text/css">
body #pageStatusBar{height:0px; font-size:0px; padding:0px; border-style:none;}
</style>

 


 

OR

Open master page through SPD. Goto code view. then ctrl+F "s4-status"
then type in style:display:none
status bar will be hidden.