Spread betting is new to me and I follow the some of the threads out of interest.
I have prior to online trading been phoned by my futures broker correcting a market order fill in my favor, never against. Online trading occurs in one of 2 ways: 1: digitally confirmed transaction as soon as the 'Buy' is clicked; 2: requote — order/price is entered, broker confirms or quote a new offer.
Obviously one wants an error against one's position corrected. Occasionally things go wrong, malfunction, fail, however irrespective the liability for quotes and fills it seems to me rests with the seller, the company providing the service product, the broker. Whether or not they choose to honor the error is another matter, whether or not they want to contact me and give me a better price is up to them.
Capitalspreads:
"when a misquote hits the screens" ??? "when a market makes an incorrect move" ?????
As to the Rolls Royce £12,000 oops ! typo ! £20,000 price tag, there's lots of examples of online pricing errors and will no doubt continue to be:
http://www.hotelnewsresource.com/article16437.html
One can trade with give and take, provided one's broker also gives, but if there are repeated phone calls "the price was wrong" to one's detriment, then it's time for a different broker, or a regulator/court case, and I'll submit that contracts are different and second to law.