I think that what you are after is something like this


Given that you have a hand, that is getting the right price to call but not to raise, what happens then if you raise

Given that you connect on the flop, you have the best of it, no doubt about it

Usually a hand that can call, but not raise is a drawing hand or a hand in danger of being dominated (An example of the first is 78s and the second is ATo)

I will only look at the drawing hand

Scenario 1
By just calling you are encouraging the players to your right to come in as well .. you have sweetened the pot and they are getting a better price on there calls
If a player to the left should raise, no harm done since everybody will just have to call a single bet and that is most likely not driving anybody out
Since you have a drawing hand, if you hit it you will have a very strong hand, that can stand a lot of callers
The price is right

Scenario 2
You raise ... suddenly you are driving the players on your left out of the pot, since there are very few hands that can cold call a raise ... so most likely they fold or reraise
Now if someone has reraised, limpers before you suddenly have to cold call two bets as well and again ... not very likely
So what has happened is, that you have reduced the price you are getting on your drawing hand

The chances on you connecting with the flop are the same



While I doubt that it is a very big mistake EV wise if we are talking about a single hand ... if done repeatedly it turns into a big leak, that will cost a lot

Which is why you see players once in a while raise with suited connectors for deception, but you see noone doing it on a regular basis

Small EV loss in a single hand ... Big leak over 10000+ hands