The fear of missing out isn't only restricted to trading activities, it is a common problem with gamblers too even if they fail to acknowledge it.
This played out greatly in the just-concluded world cup tournament, so anyone who says there is no FOMO in betting is only deceiving themselves. However, one should be extra careful as well regardless of whether FOMO is real or not, my reason is addiction; it starts like this, in the thoughts that it's FOMO, but before you know it, it could graduate to something. I like to urge gamblers to be self-aware above all, anything psychological should be handled with utmost caution instead of satisfying the feelings.
I think you raised an important point about how fomo can influence a betting behavior...so during a big events like the football world cup, it's easy to feel pressured when you see other people celebrating their winnings or constantly talking about their betting experiences. that pressure can possibly lead to a very impulsive decisions instead of thinking the rational ones... that is why self awareness is very important, you need to understand your real motivations and knowing when to stop can helps to prevent a gambling from becoming an unhealthy habit or addiction. Well, making informed decisions is always better than acting on emotions or the fear of missing out.