When the guy gives a pet to a person he should set a variable (px).
This means that if the person dies / logs out he or she will not be able to swap the pet(s) for a crystal.
This can be done very simply, I will show you an example:
[@main]
#IF
#SAY
Hello there, would you like a pet?\\
<Yes, a Hen/@hen>\
<Yes, a Deer/@deer>\
<No, I want crystals/@crystal>\
<No, I want to exchange crystals/@exchangecrystals>\
<Exit/@exit>
[@hen]
#IF
#ACT
mov p9 1
marry mob hen
break
close
[@deer]
#IF
#ACT
mov p9 2
marry mob deer
break
close
[@crystal]
#IF
equal p9 1
#ACT
give hencrystal 1
break
#IF
equal p9 2
give deercrystal 1
break
close
[@exchangecrystals]
#IF
checkitem hencrystal 1
#ACT
marry mob hen
take hencrystal 1
break
#IF
checkitem deercrystal 1
#ACT
marry mob deer
take deercrystal 1
break
close
