Yes, even 'random' spikes and dips in obscure exchanges can force-close positions on some other exchanges. 'We use the average price of 5 difference exchanges

Yes, even 'random' spikes and dips in obscure exchanges can force-close positions on some other exchanges. 'We use the average price of 5 difference exchanges to calculate the current BTC price' - then one of those random exchanges goes haywire and BTC trades near 0 on them for a few seconds. Ooops, the average BTC price just dropped 20% so we had to close your position due to lack of margin. Sorry! (This has happened several times in the past few months, for instance...)