Should I require to link my Mic4Me again in case I conduct two lessons at same venue consequently?

Not necessary.

Since the Mic4Me connection would be kept active, unless

1.  Your active Mic4Me connection is replaced by another Mic4Me;
2.  The related AV system has been reset by ITSC remotely;

No pairing is required if the use of same Mic4Me at the same venue consequently.