We have run mostly kevlar bead 28mm tires over the years with our tandem, team weight (recent -yay) 300 to (previously) 340 (not including bike). Never a problem with bead seating. Can't imagine how you would run into trouble with kevlar bead as described. We like the other advantages of the folding tire, especially on tour. I should say that folding correlates with pliable side-wall, too. And pliable side-wall yields comfort and low rolling resistance (if I get the thrust of various and sundry postings here and otherwise). I don't think safety is the deciding factor as you have presented the issues.