Good luck with catching spawning trout (sarcasm intended). Try it sometime if you want to prove my point. They are not like bass that will remove an intrudier, including a lure, from the nest. Nor are they like crappie or bluegill that are exceptionally vulnerable during spawning.
Just as one additional comment….Do the same people here who object to fishing over spawning trout also object to fishing and harvesting the aforementioned panfish when spawning given that they are much more vulnerable and clearly documented to show the negative population effects of overharvest? Where pressure is high stunting occurs in the BG case when harvest of large males is high. This is common in Pa. Likewise, cropping of crappie down to a much smaller size than their potential would allow occurs in waters where crappie growth is not limited by forage, water temps, or limited dissolved oxygen in the thermocline or thermocline/epilimnion interface. Just wondering if anglers who object to fishing over spawning trout are consistent in their thinking, especially regarding much more vulnerable species at spawning time. If not, why not?