I did a bit of an experiment the past couple of days. I stuck some 1" squares of white gaff tape on my P85D where the AP2 sensors are. A lot depends on how much obstruction will cause how much of a problem. The worst is my rear camera that can become effectively unusable in about 10 minutes of driving. The ones in the turn signal / badge were next worse. The worst salt spray here was from the front tire so if these may not do too badly if they are recessed enough to prevent this. The ones on the upper pillar between the front and back doors got fairly gummed up yesterday morning (36f after several days of snow and salt application) but since then have remained clean.
Assuming the 3 in front are cleared by the wiper and the heaters work well in all of them then they may work most of the time. Of course, that still leaves the problem of the radar and prox sensors.