At Blackpool this year, there was a bottle of fizzy drink where we were standing, and one professional latin couple (not sure who) opened this drink, poured it on the floor and stood in it, presumably to make their shoes sticky (I was just stood staring in disbelief at the cheekiness of that!).
I'm sure Ian said years ago on ITT they use Coke etc to make their soles sticky.
Dancers also use oil etc to make their shoes more slippery so they haven't got as much friction between them and the floor I presume.