Wideband air/fuel gauge question

I got my FAST a/f gauge installed, did a quickie deal since I plan to move it from car to car....

...seems to work pretty well for a basic gauge/playback device, but I have a quick question:

Will pan evac mess up the accuracy, or damage the o2 sensor?

I have the 02s a couple inches upstream of the pan evac outlets (which seems OK), but I'm pretty sure they do try to backflow under decel....otherwise, they wouldn't need check valves....

yes, the pan evac fumes/gasses with throw the 02 readings off.
Leaded race fuel will kill the sensor over time, BTDT.

Thanks! ...was somewhat concerned with that, don't want to mess anything up. I'll pull the hoses off for now.