Yup, nothing legally binding absolutely. I think for most of us here that are under a 7 digit networth, the trustworthiness of a local broker vs ibkr etc isn't worth taking into account yet. The chances of IBKR going the way of MF Global is exceedingly low.
One thing I might do if I ever get to a large enough portfolio, is to diversify brokers by shifting the "never to be touched" index fund portion into a "closer to home" broker like dbs just for peace of mind.
I split my local and foreign portfolios......For local shares, I went with Tiger and DBS Vickers (including SRS). For foreign shares, I went with IB US. I think IB US is still available on joint account, for people who want SIPC protection up to USD 500k.....
Personally I think the chances of IBKR blowing up is less than 0.1%, Haha