IT’S COMMON PRACTICE for some writers to conclude that showbiz couples going abroad together will be tying the knot while they’re away. Bea Alonzo and Zanjoe Marudo are now in Paris for a TFC promo show and it’s said they’ll have a secret marriage while they are there. The same goes for Robin Padilla who took wife Mariel Rodriguez with him to Paris also. They’ll take a side trip to Rome and writers are saying they will exchange vows at the Vatican. Then there’s the controversial couple, Dr. Vicki Belo and inamorato Hayden Kho. They’re now in the Machu Picchu ruins in Peru and again, wags are saying they’ll exchange I do’s while they’re there. Of course, when these couples return, expect the predictable rounds of the usual denials.