Last time there was a big IT issue (May 2017), it took about 72 hours to correct. We caught the end of it but it was a really tense start to the holiday at Terminal 5 with flights in front of ours popping up as cancelled. I guess it depends on the size of the issue. I’d imagine you’ll be ok by Saturday and I’d proceed as normal but perhaps have a conversation with the DC about what’s going on?
We have just flown back from San Francisco. We sat on the runway while they manually worked out which bags needed to go where in order to balance the plane. Bags came fine though. They prioritise long haul over short haul.