Split Requests

Split requests seem to be all the fashion lately. I know they're perfectly legal, though I haven't read the rule itself. I'm wondering about them though ... It seems oddly unfair, for example, that a person never (or rarely) swimming open 50s could hold world or national records or #1 rankings in those events. (I'm just saying it's odd, while recognizing it could be perfectly legal.) But, aside from that and further, what if someone really played the system. What if, for example, someone was after a 50 free record. They entered a meet in the 50, 100, 200, 400, 800 free and led off free relays and requested split requests in each event to try to set a record. Is this legitimate or legal? Would a meet director be bound to accept split requests for all these events? Is there a limit? Do meet directors have discretion to deny multiple split requests? I can see a situation where multiple attempts at a 50 might result in a better time ...