Absolutely a valid point and possibly a concearn, but it's going to be hard to have everyone agree on one way or another. Aswell, this may lead to complications during mercies on the field as they happen.
Just imagine that you are using a 400fps upgraded AEG and you get the drop on someone. You declair mercy on them as they stick their noggin out from behind a tree, but in a split second they react by pulling the trigger of their (unbeknown to you) stock gun, and with out thinking beyond "that sob's declining my mercy", you pull the trigger.....instant incident.
Now imagine you are the poor guy with the stock gun who was startled by the guy yelling mercy causing you to accidently squease that trigger...
Unless it is clearly defined to everyone at the begining of a game, and originally posted as a condition set by the game host from day one (so players know what ios expected of them), there will be problems.
It may transpire quickly and easily...but then again too many people are set in their ways and there is always those hard learner cases.
On a side note for other readers; you may be aware that we have established minimum safe shooting distances for bolt actions (which are allowed a higher fps to offset a lack in ROF) but not a mercy rule......to simply put it an upgraded bolt action operator is not allowed to mercy anyone with their primary, and here's why;
a fully upgraded level 2, that's a 200% spring or equivilant, bolt action rifle will crank out 0.20 weight BB's at over 500 fps, hench forth you do not shoot at anyone with in 100 feet.
So, then why would you even point your upgraded bolt action at anyone with in 10 feet and risk a misfire???? (and yes, I have seen mechanical failures that have caused chambered BB's to be fired prematurally).
The idea of the sport is to have fun, not injure people, and trust me, you don't want to be on the business end of a bolt action if that happens.
Mr.C (madmax) is headed in the right direction with this....but I hope it dosen't get to complicated.
Good luck bro; SHA DO