I conservatively estimate that at least one 1B is playing SS in each division.
Now, we have to remember that 1B don't have nearly the range of a SS, so they won't get to as many balls as a true SS would, and so their actual "fielding" or "gloving" of a ball will tend to be higher than otherwise anecdotal evidence might possibly indicate, since the "chances" they get will be of the easy type, comparatively speaking (though some might point out that RL "SS" JJ Hardy has also got lead weights in his shoes and may better resemble a 1B in this regard, that is, range).
Anyway, the point I am so belaboredly making, or not, is that these 1B may hurt the team with their limited range moreso than their actual fielding errors since the balls they get to they should be able to handle relatively easily, being experienced as they are at scooping low throws off the ground, which are grounder-like in velocity and trajectory.
But then again, once having succesfully fielded the ball, there is the slight complication of throwing it. Which adds a whole new calculus to the discussion.
So maybe it all works out in the end.