Slots (and CTMS times) are 'strategic' as an ATC I couldn't tell you what slot time you actually got unless you depart somewhere like Canberra then I can spot you in the "Flow tool" MAESTRO before you depart. Perhaps the info is available somewhere, but certainly not to the operational ATCs (maybe the flow gets a copy, but I doubt it)
For everything airborne it's tactical flow; if you are trying to arrange your flight for a specific strategic landing time, with the inaccuracies of everybody else flying it won't effect what happens to you airborne.
Re CTMS times, a certain regional airline was renowned for ignoring them; until a full audit was conducted; then when discovered some harsh words were had and compliance of CTMS time commenced across the board with threats of 'withdrawn slots' etc. But they got away with it for years, as no operational ATC cared because we didn't have the information about the times and it was only been counters who discovered it when trying to work out why CTMS times didn't solve all the things they were supposed to save.
Underdog, if the gap is there wouldn't you rather fill it; or keep the gap and delay the rest of the sequence? Sometimes they do just happen. Think about a line of 'crawling car traffic' on a single lane road due an accident or something, you don't cruise along at a constant reduced speed, if someone does then there is a hole in the line of cars; increase speed, get overtaken or the gap remains...