The club will have to shoulder some of the blame, perhaps this is just hindsight, but surely someone who works for the club should be responsible for checking in / out items that are brought into the stadium, especially fake devices?
It's a little bit naive to trust a 3rd party company to do their job properly, regardless of what they specialise in / how experienced they are, ultimately somebody at the club should have been aware exactly what was happening. Of course the security company should take the majority of the blame, but I certainly don't think fans are overacting when they say this is shambolic.
The refund is a nice gesture but I'm sure I wasn't the only parent / grandparent having to keep a young Utd fan positive last night, for someone who has been looking forward to the game, listening to Utd stories and building up to the event for 2 weeks, it's fecking heartbreaking.
All in all, regardless of who is to blame, it's a complete and utter farce, one that could have led to serious panic and it's a bad day for the club.
Also, the rescheduled game, why put it at 8 o'clock? play it at 5 and let the school kids watch it.