Quick suggestion....
As the forum continues to add more and more threads on sandbagging after a certain point it becomes a little ridiculous.
Here is what I think.....
Match play just as stroke play should also effect your tier movement. A majority of the match play baggers are pro level players. If your match play percentages could also effect your tier moves then the amount of baggers should significantly decrease.
I think the above is your best option in eliminating a few baggers
Just my 2cent