When using the following code in PowerShell 3.0
PS> $data = Invoke-Webrequest -Uri stackoverflow.com
PS> $data.ParsedHtml.getElementsByTagName(\"div\")
The message can be suppressed by loosening the privacy setting in your internet options 
You can also just add a per site pricavy option for the site you're using in your script, instead of allowing all cookies.
Opposed to the -UseBasicParsing You'll keep the parsing provided by internet explorer. (At the cost of loosened security)