You can chose how many teaser videos you offer to your non-members. Select between “None”, “All”, and “From the last four weeks”.
Selecting “From the last four weeks” has the advantage that you always offer some fresh new content but not giving away too much content for free. Teaser videos from collections created more than four weeks ago will be hidden.
Find the option in your shops’ preferences.
UPDATE: It is now possible to select “From the last two weeks”, too.