The following is a quote from my Aerius i manual (which also uses the plastic strips:
"The clear Lexan panels on the back of the Aerius i stator are the key elements of an innovative pressure compensating technology. Martin-Logan is able to tone-shape the diaphragm + or - 6db without the use of an insertion loss crossover. The advantage of this system is a high efficiency driver with wide bandwidth capabilities of dimensions which are easily integrated into a domestic environment."
Whew! I can't figure out what it means, technically, either. And it looks like Martin-Logan may not know too
since they left this paragraph out of subsequent manuals.
Practically, what it means is: Leave them alone!