I am wondering about the choice of, and general necessity of, なら in the following sentence.
ドイツでは、ウイルスがうつらないように気をつけているなら、店を開くことができます。(from NHK Easy)
* In Germany, businesses may remain open if they are careful not to spread the virus. (my trans.)
According to DBJG, なら means roughly 'under the condition that something is true'. How does this work in the context of the above sentence, in particular why would たら not be appropriate, since (in my mind) any if-clause always assumes its own validity.
Does the なら carry a sense of "actually" or "really" here? For example, would it be more accurate to translate the sentence as "... if the businesses are really ensuring the virus doesn't spread"? Or does なら contain a sense of "so long as", i.e. suggesting that the condition is liable to change over time, "...as long as the businesses are ensuring the virus doesn't spread."?