>>20424763Y-zard requires hazard control, but that's a thing on a lot of teams.
Y-zard is much, MUCH better with pursuit support, so Charizard+Bisharp is probably Y and Charizard+T-Tar is almost definitely Y, cause T-Tar cancels out sun, so like if Y-zard needs to switch out, but then switch in again after a couple turns, it doesn't suddenly find itself with only a single turn of sun left.
Y-zard works very well on one specific team. X-zard works on several teams.
https://www.smogon.com/forums/threads/force-of-nature-an-in-depth-guide-to-zard-y.3501476/Zard/hazard control/pursuit trapper/Keldeo/bird check/rock setter. If you see a team like that it is guaranteed to be Y, unless they're specifically running X to fool you but then they end up with a shitty team. There are other teams with Y but they still have the red flags, the aforementioned pursuit trapper and defogger. If they don't it's a shitty team.
Of course recognizing which zard it is based on the team doesn't work in low ELO because most people there just use zard cause it's their bro or whatever. I'd assume it's X cause a). It's cooler and twelve years olds like cool things, and b). guessing it's X instead of Y and being wrong means you lose a mon to sun boosted Fire Blast, guessing it's Y instead of X and being wrong means it gets a free turn to DD and then you lose.