You can definitely compete on unloading weeks; and it’s not like you have much of a choice in the collegiate system. In any case though, competing on unloading weeks isn’t a big deal because the volume is so low like you mentioned. In fact, it’s my experience that some of the best performances come in these unloading weeks. As such, they are perfect weeks to perform field tests on as well as low key competitions.
One thing you might want to consider though is if you’ve only been training 5 days a week all year (Mon-Fri), competing on the weekend (regardless of how low the volume on meet day) would still be turning a 5 day cycle into a 6 day cycle…..that’s not exactly what I’d call unloading 🙂
The ideal situation is that you’re already training 6 days a week and then it wouldn’t be a big deal. If however, you’re only training 5 days a week and a meet falls on a day that would typically be off on a week that is also an unloading week you might want to drop a training day during the week (wednesday would probably be the best day).