In 16 years I have had 3 or 4 occasions where my ladders have slipped and I have fallen. Each time it was my error for which I take full responsibility and wouldn't bleat about it if I had been hurt. I am not saying it couldn't nor wouldn't happen again, or that I won't get hurt should it happen, but I know and accept the risks and take more care to minimise the chances of it happening by using the ladders more responsibly.
FYI, the only wf poler I know of in my locality is a good friend of mine who is semi retired and is unable to use ladders due to a serious injury he sustained 2 years ago (not involving ladders).
John