Care must be taken that no liquid enters the small gap between the glass and the covering framework at the sides. The consequences are not very severe but it could complicate the removal of the dried film. It is recommended to keep a small gap to the edge of the filter.
I'm actually worried about the shutter unit, and also the part about the fluid seeping into areas past the AA filter. The AA filter per se would be covered in the film so there's no worry about whatever dust entering.
if the shutter unit is kept open for two hours, sometimes battery will run out.
my camera does not allow the shutter unit to be kept open if the battery runs out, it will just happily flip down the mirror.
looks too fiddly for my liking.
wet cleaning is easy, safe if you have the know-how and take the necessary precautions. the filter over the sensor is not made out of play dough, we give it too little credit sometimes in terms of durability.
got so many ways how this film thing can go wrong. sama sama.
anyways, i've seen pictures somewhere of wet cleaning fluid (applied too liberally) going underneath the sensor. in such cases, more is not better.
In the video they say that the gimmic they do with the paper strap (sticking both ends of it on the film) is done so that shutter won't be harmed on closure though it will make the film dry even slower.
This isn't something I will try at home either. I just think that it should be very effective. They also admit that the film works only on water soluable impurities, not things like finger prints.