The thing the Notts fire officer omitted to say was that if said restaurants wash up properly, their dishcloths shouldn't get so greasy in the first place. Next step: salmonella.
Round here we rinse properly after the washing up water before drying up - everything stays cleaner, sink & drainer, plates and utensils, and tea-towels especially.
IMHO, it's a good argument for finding somewhere else to go for a Saturday curry, or whatever.
I've come close to having a fire with solvent-soaked paper towel, and others on here have actually had it happen. I've a feeling cotton rags are more combustible than the paper towels tho, and I don't use them as often. Call me messy, but soaked rags and paper towels now get thrown out of the workshop door, and left outside until there's no danger of anything interesting happening. I've got an old cast iron saucepan that's a good safe place to put them (with chicken wire on top to prevent them going airborne).