[AccessD] checkbox concatenation

...given four tables

   tblContact pk ContactID fk CompanyId
   tblCompany pk CompanyID
   tbEvent pk EventID
   tblEventReg pkERID fk EventID fk CompanyD fk ContactID

...tblEventRegistration is a join table to show which contacts from which 
companies attended which events.
...given that thousands of contacts attend each event, tblEventReg is 
growing logarithmically

Q: is it feasible to use a numeric field in the tblContacts to replace 
tblEventReg by using event checkboxes instead, assigning them a numeric 
value by show and then mathematically summing them in the numeric field 
...thus using one integer to represent every event attended by that contact? 
...yes/no? ...pros/cons?

William Hindman