No no, actually the first s is /s/ i.e. voiceless as in "sea" or "pass", so the complete transcription should be /kʀiːksʃpiːl/. The transition between the /s/ and /ʃ/ is then just making your lips round for the /ʃ/ after the wide and flat /s/. It is still not as easy as just leaving it out, but it is whole lot more doable.
I'm not saying that's why this alternate spelling has arisen, but it could be a transcription of a mispronunciation.
[0] IPA /ʃp/ rather than /sp/ because initial 'sp' in german is pronounced that way. I don't know if this rule has a name... "post-alveolarization"?