I concur.
What seemed obvious to me was the English grammar of the sentence--it had very little to do with ASL itself. (Any squad may place a foxhole above itself by making a successful dice roll.) To me, the "may" indicates only that the squad has the choice of attempting the dice roll.
From the ASLRB introduction:
For example, if a rule states that a MMC can perform a particular action, then only that unit type can perform itβdonβt think that several SMC can do it simply because the rules donβt list that type as being unable to do it.
Let me paraphrase that statement to show you how I think COWTRA applies in this situation:
For example, if a rule states that an MMC, on performing a particular action, is placed beneath a Foxhole counter, then the only possible outcome is that the unit is placed beneath a Foxhole counter--don't think that the MMC has the choice of not being placed beneath the Foxhole counter simply because the rule doesn't prohibit that outcome.
And you too!