I finally found the modern CDC estimates for HIV transmission based on various circus acts on this page in Table 5.

The risks are substantially different than I had remembered. This paper elsewhere stresses these risks seem to vary highly from person to person and based on the presence of other STDs.

It's especially worth noting that condoms only decrease risk by 20:1. That's substantial but no magic bullet. No wonder gay porn is a disaster.
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"If they can't picture me with a knife, forcing them to strip in an alley, I don't want any part of it. It's humiliating." - windsock