You need to elaborate some. Are you referring to Splunk Enterprise, Splunk Storm, or something else entirely?
If you are referring to Splunk Enterprise, the answer is no. You host and run this yourself, and Splunk the company has no access to your data.
If you are referring to Splunk Storm, then it is possible that certain Splunk staff members would have access to your data as part of their role in supporting the Storm service. But, the data you store in a Splunk Storm project is your data and Splunk generally has no right to use it except for in connection to supporting you as a customer.
If you are talking about something else entirely, then you'll need to edit your original question to say what that is.
And, of course, this is a layperson's interpretation and comes from someone who does not work for Splunk. For a more precise evaluation, I would recommend your lawyer review applicable software license agreements and privacy policies provided by Splunk.
