Personally, I would like to see more players actually use the bats that they are sponsored to use rather than sticking labels from a brand on bats that they have sourced from another supplier
So would I, but sponsorship is a big part of the modern game whether it's a large cricket company like GM, SS or something unrelated like MRF...I remember wondering who they were when Sachin was the first to advertise that company.
It's unrealistic not to think any player would take as much money as possible and maximise their earnings in today's sporting environment, it can be a short career and that goes for any sport.
I do think if you are sponsored by 'X' company you should absolutely make sure their sponsorship is visible and no one else's...
Whether those players use another brand has gone on for years and probably will continue. smaller manufacturers may have a relationship with X player but are not financially able to offer a sponsorship.