Walking with SPD-SL cleats is not a problem. The cleats are made of plastic so you may want cleat covers if you plan on doing a lot of walking on rough surfaces.
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.