Future Employment Restrictions with TCS/Infosys?

Hi everyone, I’m considering offers from TCS and Infosys but have heard some concerns that I'd like to clarify. Specifically, if I accept an offer from either company and then decide not to join, how long might they block me from future opportunities with them? Additionally, I’ve heard that if you leave TCS after joining, they might not rehire you in the future. Has anyone experienced this or have more information on these policies? Thanks for your insights!