I can't find any rules prohibiting such an action although it feels a little strange.
As you already said, there is NO rule which prevent this, so this is allowed!
And i don´t think this is strange, a Square unit it very vulnerable against INF attacks and many range attacks too (because they get no support to ignore flags).
And my general personal question about such subjective estimate is always:
"How many games you played (please dont count Solo games, they are useless). I have played in meantime hundreds of games and it was never strange (if the square was really recovered, most it was much more sense, to recover other units)"
