This is why I'm buying a substantial amount of btc before my trading break rather than cashing everything out and buying back in the trend reversal - the risk of the two fiat transactions - cashing out and depositing back in, will outweigh the gain on the trade of whatever is left of the downtrend at this point. Who knows if... by that point maybe my bank will have put some block on bitcoin exchanges and I won't even be able to get back in as it's breaking out.
On the other hand, building a reputation of habitually moving "large" (the bank-large is now hardly a monthly salary in many places) balances can enable you to do it when you really need the opportunity. Sudden large (albeit completely legal and documented) activity may cause you problems, because the banks these days are very much constrained by the controllists.