Penalty for Failure to Give Best Effort

13.G.2.h.  Failing to give best effort in play such that the referee determines, based upon the totality of circumstances, a player or team intenti0nally faulted on a serve or intentionally lost a rally, with the purpose of favoring their opponent(s).

None, although 13.M. is related.

If players knew a "serve around" would result in a negative point differential, that should discourage this conduct.  Although guidance has been given to referees on how to handle the serve around, should one occur on their court, if the goal is to prevent those instances from occurring, there should be a rule in place and concomitant penalty that would discourage this conduct.  Alternate penalties or ways to address this conduct are not as effective.  For example, if the referee addresses the conduct by proceeding with the side out while issuing a TW, the offending player has been successful in benefiting their opponent while only receiving a warning.  Alternatively, ordering a "re-serve" in an attempt to remove the benefit of the serve around is suboptimal for two reasons:  It leaves the referee with no recourse if the next serve looks as though it was made with best efforts - but sails a bit long.  Secondly, a "reserve" gives the player a second chance to follow rules they knowingly violated, which is inappropriate in a tournament setting.  I am making this rule suggestion because it seems to me, if there is a clear workable rule which applies to a player for failing to give best efforts, it would be less stressful on referees should that scenario occur, and, moreover, that offending conduct would be less likely to occur.  (At this point it appears the only rule on this issue is one which empowers the tournament director to expel a player for not making best efforts in games or matches, plural.  13.M.4.  I would argue that rule should not apply to a single rally.)

Using a singles scenario for simplicity:  Hypothetically, the server is faulted for not serving within 10 seconds and a side-out is called.   The faulted server expresses frustration with the referee and the opinion that he/she should been allowed more time to serve for whatever reason, maybe they are trying to save a bug they would have stepped on had they served.  The opponent receiver expresses agreement that the server should not have been faulted.  After the side-out, that opponent is now the server and when he/she serves, they do an obvious high toss, allow the ball to bounce, then hit the ball to serve.  The server is appropriately faulted for an illegal drop serve, side-out, TW.  If players were aware that conduct would result in a TF, it likely would not occur.