I really don't think so. On the Ameristeps, the two top ones are just in the corners of the square "pads", so even if that little corner were to break, which I don't think it will, it wouldn't stop the step from functioning normally, IMO. The bottom one, being way on the end, would be the same situation, IMO. So, I don't think the step's ability to support weight would be affected in either case. The real strength of the step is up and down the center "rib" and mostly above where my bottom "cleat" is. On the Silent Approach steps, I placed them at some of the thickest areas and again the bottom one is right in that center rib area. And on these, the material is almost more like a nylonish stuff than a plastic. As a machinist for the last 40 years, I have found materials like this are not brittle, and almost indestructible. You would need to make your own call on whether you would trust steps modified this way but as for me, I have complete faith that they will hold up just fine. Also worth mentioning, the Ameristeps are my ROS, so not supporting my full weight, like they would if used to climb. And the Silent Approach steps will only be used for my bottom two steps if at all, so not as important as what supports me higher up.
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