This short popped up in my feed today, and it reminded of a Twice thing I found really endearing. They have incorporated how to do fanservice in their security protocols. In the short I linked, you can see how the senior guard is telling one of the other guards to back down a little and give Nayeon the space to say hi and wave to fans for a bit.
We also see this in the concerts a lot. The Twice Team security guards regularly take things from the fans, so that the girls can do fanservice. This is how props like the huge candy bongs or the goofy hats from fans eventually end up with the girls. They have also taken stuff up to sign and bring them to fans. It's pretty clear to me that there is protocol and directive on how to do this in Team Twice because regular venue security do not do this for them.
I just find it so endearing how the girls like fanservice so much that they tried to find ways on how to do this safely at their scale, and now it's part of their security protocols.