so a car company sell me a car and sign me on agreement saying i'm driving at my own risk and then the breaks fails they are not responsible? i doubt it.
Exactly. For high networth individuals, who spread assets among different brokers, it's fine. If you want to be flat on an open position but can't log on, do an opposing trade on the one that works, and next time both brokers work you close both together. But even the above doesn't work if it is a position that is expiring when you can't log on, like options trades. Over the weekend, the other positions are no longer delta neutral when the original ones expired on friday. But as far as IB goes, IB as a broker offers services that frankly no other broker offers. If you are trading obscure products that only IB gives access to for the retail gamer, then you're stuck. It's not like you can run to thinkorswim and close out products only IB offers. But for many traders, they actually want to concentrate assets in one broker to have the largest margin available to them. Unless you qualify for prime brokerage service as an institution who can manage different accounts under one buying power roof, having multiple accounts don't make sense for people who regularly maximize margin use.
I'm aware of that and still IB have a liability when their system fail. they can sign you whatever they want but the law not necessarily take that as words carved into the rock.
That's true. A lot of people here probably saved money by not being able to trade today. ;-) They are probably having a better Friday because of it.
I believe that having a backup brokerage account is more trouble than it is worth for all but the largest traders. More account management work, more tax prep work, and it reduces the available balance for doing single, large transactions. Plus remember that having two brokerage accounts means that you will have twice the number of outages. But what traders need is a plan to cover various types of outages. If the power or internet goes out at home, know in advance where the closest places are for you take your laptop and continue trading. If your desktop trading workstation is not working, know in advance, how to perform trades on your account using all available methods - the web or mobile. As someone else mentioned, you could still place orders with IB if you could get the price data from another source.