They will only be interpreted as scalars if you eval them... if a $ is in a string it is only a $... example

$test = 'ab$cd';
print "$test\n"; #prints ab$cd\n
#only when you actually have the $ in double quotes...
print "ab$cd\n";
#do you need to worry about it
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Update but if you were evalling it you could do

eval "\Q$test\E";
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the \Q \E goes through a string escaping (\$) all non word characters.
                - Ant