Vegas had guys who were actually, legitimately injured - they stayed on LTIR during the playoffs, and their playoff roster (guys who actually played) was never over the cap. They might have delayed Stone's return for cap reasons, but were still cap compliant with the guys who played in the playoffs, pretty different from the Tampa situation. And I doubt they delayed his return much - he had a legit back injury, had surgery for it in February, him coming back mid April is about right. His back also seemed to be flaring up and bugging him throughout the playoffs.
I do think Tampa cheated - Kucherov did get injured, but it really seems like he was healthy well before he came back, they delayed his return until playoff start to circumvent the cap, and their playoff roster was WAY over the cap. But even there, Kucherov was actually injured for most of the time he was out - a player might accept "come back from your injury a few weeks after you're healthy", they aren't gonna accept "skip an entire season of your career, when you're healthy." Has literally never been done, and won't happen.