MD900 - fair point, well made !!
Weight can be a problem especially if the pillion is heavier than me but normally, with appropriate safety briefing (i.e. put your hands round my waist, follow my body movements and if in doubt bl**dy well sit still and DO NOT put your feet down), I have not found it to be an issue. I ride a Bonne so speed is hardly my top priority.
Whilst I have taken women on the back of my bike that is because we are close friends not because they are... uhm... fit birds
However, strapping young men..... that's a different matter
Cheers
Whirlygig