I used to use those paper B + Q ladders when i first started out , i too would advise somthing a bit more sturdy , i never had a prob with them safety wise , but one day i left them against a house wall and when i came back to get them they were laying across the bonnet of my customers BMW !
I was lucky all they did was scuff the laquer , and the smallest of creases you could just about see , the owner said he only saw the crease because i pointed it out , i Tcut the scuff and no more was said ... PHEWWW !
Rich P @ F