Joint bar / fish plate usage

Have found many joint bars and joint straps along the logging grades, but have now found at least half a dozen that make me inquire as to what possible reason the RRs in the area would have to take joint bars or straps and drive spikes through the bolts holes? I am pretty sure they didn't use the spikes in lieu of bolts (I sure hope anyway), so any guess from the more knowledgeable as to why? I have now found a minimum of six bars or straps that have all had multiple spikes, usually three or four, driven through the bolt holes and still affixed to the bar or strap, the strap always being complete, affixing it to I assume a tie... maybe? Bracing something??? Part of a stub switch or??? Used in some type of construction? Ranchers / Farmers have been using them for centuries to ward off predators? Somebody did it to make me ask questions? SWAGs welcome since I don't have one.