What I generally do in this situation is not actually direction users to the actual list/form.
After I create the infopath form, I create a new page. I add an Infopath web part, and point it to that list (it's very easy if you haven't done it).
This is what I do on the infopath form.
- Open Infopath
- Click on PAGE DESIGN, click on NEW VIEW
- Create a new view.... call it "thank you" and put some thank you text
- Click on DATA, SUBMIT OPTIONS
- Make sure PERFORM CUSTOM ACTION USING RULES is checked, click OK
- Still on the DATA toolbar, click on FORM SUBMIT (it might have opened up)
- This should bring up rules on the right
- Click on NEW, then ACTION, leave the default condition (it may have already this as well)
- Under RUN THESE ACTIONS, click on SWITCH VIEWS
- Choose your "thank you" view
- Click on RUN THESE ACTIONS again, click on SUBMIT DATA (if there isn't already a submit data added by default by Sharepoint)
- Save and Publish your form
That should do it. My directions are just a touch rough because sometimes after you choose "Perform Custom rules" sharepoint will add a rule automatically. I've had it not do it as well.
This gives you the flexibility of direction users to a page that you can easily customize if need by rather than taking them straight to the list.