When you have a weakness from balls coming in from wide areas, you do what you can to negate it. I'm just surprised they thought of it.
Given it's annoyed a few Morton fans, I hope it's replicated by other teams mainly to highlight their managers tactical limitations.
These sorts of things have boon going on for ages, no tables in away dressing rooms, no hot water or heating switched on etc. One of the best examples - although it is rugby - is the big obstruction in the middle of the away dressing room at Murrayfield. They allowed folk to think it was to cover something to to with the stadium construction but it's solely to make it more difficult for the away team.
Best bet is to not let it be known that these things have not had an effect.