If lenses are cut to size, or slightly oversize, they should not fall out due to the deeper groove design of our Dilli Dalli frames. They have been edge tested to very steep RX prescriptions without incidence.
Of course, it is possible with extended pulling and tugging to dislodge a lens, after all lenses are not permanenly inserted, as they need to accomodate a new presection. Although it is not the norm.
If lenses do pop out, we recommend you bring them to your eyecare professional, as it is possible to insert them incorrectly.