It's a terrible event and brings home the vulnerability of places like this to this type of attack.
My point however was not really about any escalation in threat - going back I remember being warned about bomb threats from the IRA at assemblies when I was a child in the late 70s and early 80s.
All I was saying is that mandatory training for attendants has been a feature of assemblies in the UK for years. Bag searches have also been around for at least two years. Brothers have had increasing secular certification requirements here over the past 5 plus years. It's started years ago with low key with mandatory events covering duties, safety etc, having to wear high viz tabards, early morning briefings for the entire cohort before the doors open, special attention being paid to those that don't have a badge etc. but has increased over the years, driven by secular obligations either with the law or from what the venue has imposed.
For example, when we first met at the Brighton Centre (early -mid 90s) the venue said we could not use attendants, we had to use their staff. This represented a significant cost but the assembly team managed to convince the venue that the Witnesses were experienced and could cope with the H&S requirements. They only agreed once the team agreed to a day long training event that would be mandatory for every attendant. This pattern has been followed every year since, continues now the venue is the Amex stadium and has been introduced for every assembly location in the UK for years.
Requirements may once again have increased this year but for the UK it's not a sea change as many of the mechanisms they are talking about for other places have been gradually introduced here already.
It's not a big deal overall but I just don't think that UK attendees will see anything significantly different to that they have already experienced.