Well, rule #1, never convert your bitcoin back to fiat. The banks and governments wants a cut of this. If you are trading, convert everything back to bitcoin, and keep it in this currency.
fiat is the most insecure thing ever, not because of theft, but because of governments. I'ts like their last grasp before we become free
Sometimes you have to have fiat or you need to hedge against a big drop in price.
If banks are freezing accounts it is likely due to huge amounts of money being transferred and them informing the tax authority that demands temporary freezing untill the funds can be explained.