Logically speaking I too would have thought it would fail with no wipers. Even if you say that it will only be used in summer/ dry days, what happens if you are driving & get sprayed by a field-sprinkler (those mahoosive buggers) or someone in front sprays theirs screen whilst travelling. you will have no way of clearing it. It's a safety issue.

If you do wanna be able to take it off..how about a single conversion to start with. That wil get rid of one straight away. For the other, how about modifying the wiper arm & the motor arm. Normally the spigot fits through the top panel & the wiper goes onto that. You could modify it the other way round. Have it so that you bolt the wiper through the panel & then put a nut to secure it to the motor arm. This way you could take it off when you wanted & fit a colour coded bung so it will look flush and won't have the arm poking through the top panel like normal.