If they took the time and effort to hack somewhat competently, no.
And for RNG, you more or less can’t see them without being able to view the data.
Anyhow, even if they didn’t hack competently, well, even so, you won’t really be able to without access to viewing the team’s summary.
if you could view the team’s summary, at least *maybe* a few things will pop out, like multiple a Gen 9 Pokémon being caught on the same date with all perfect IVs (you’ll need the IV judge for that), and maybe a bunch of shinies on the same date even if they aren’t flawless in stats. Maybe they weren’t caught in the correct location.
It’s not gonna be easy for players with access to the data, and even in situations that people has access to the data (like event staff), they may not know what to check.
Anyhow, I believe RNG manipulations isn’t the problem that was highlighted (also I wasn’t answering to that either), but rather it was bad hacks that didn’t take legitimate RNG sequences into account, hence giving a concrete reason to show they were hacked.